# MatrixTable¶

class hail.MatrixTable[source]

Hail’s distributed implementation of a structured matrix.

Use read_matrix_table() to read a matrix table that was written with MatrixTable.write().

Examples

>>> dataset = dataset.annotate_globals(pli = {'SCN1A': 0.999, 'SONIC': 0.014},
...                                    populations = ['AFR', 'EAS', 'EUR', 'SAS', 'AMR', 'HIS'])

>>> dataset = dataset.annotate_cols(pop = dataset.populations[hl.int(hl.rand_unif(0, 6))],
...                                 sample_gq = hl.agg.mean(dataset.GQ),
...                                 sample_dp = hl.agg.mean(dataset.DP))

>>> dataset = dataset.annotate_rows(variant_gq = hl.agg.mean(dataset.GQ),
...                                 variant_dp = hl.agg.mean(dataset.GQ),
...                                 sas_hets = hl.agg.count_where(dataset.GT.is_het()))

>>> dataset = dataset.annotate_entries(gq_by_dp = dataset.GQ / dataset.DP)


Filter:

>>> dataset = dataset.filter_cols(dataset.pop != 'EUR')

>>> datasetm = dataset.filter_rows((dataset.variant_gq > 10) & (dataset.variant_dp > 5))

>>> dataset = dataset.filter_entries(dataset.gq_by_dp > 1)


Query:

>>> col_stats = dataset.aggregate_cols(hl.struct(pop_counts=hl.agg.counter(dataset.pop),
...                                              high_quality=hl.agg.fraction((dataset.sample_gq > 10) & (dataset.sample_dp > 5))))
>>> print(col_stats.pop_counts)
>>> print(col_stats.high_quality)

>>> het_dist = dataset.aggregate_rows(hl.agg.stats(dataset.sas_hets))
>>> print(het_dist)

>>> entry_stats = dataset.aggregate_entries(hl.struct(call_rate=hl.agg.fraction(hl.is_defined(dataset.GT)),
...                                                   global_gq_mean=hl.agg.mean(dataset.GQ)))
>>> print(entry_stats.call_rate)
>>> print(entry_stats.global_gq_mean)


Attributes

 col Returns a struct expression of all column-indexed fields, including keys. col_key Column key struct. col_value Returns a struct expression including all non-key column-indexed fields. entry Returns a struct expression including all row-and-column-indexed fields. globals Returns a struct expression including all global fields. row Returns a struct expression of all row-indexed fields, including keys. row_key Row key struct. row_value Returns a struct expression including all non-key row-indexed fields.

Methods

 add_col_index Add the integer index of each column as a new column field. add_row_index Add the integer index of each row as a new row field. aggregate_cols Aggregate over columns to a local value. aggregate_entries Aggregate over entries to a local value. aggregate_rows Aggregate over rows to a local value. annotate_cols Create new column-indexed fields by name. annotate_entries Create new row-and-column-indexed fields by name. annotate_globals Create new global fields by name. annotate_rows Create new row-indexed fields by name. anti_join_cols Filters the table to columns whose key does not appear in other. anti_join_rows Filters the table to rows whose key does not appear in other. cache Persist the dataset in memory. checkpoint Checkpoint the matrix table to disk by writing and reading using a fast, but less space-efficient codec. choose_cols Choose a new set of columns from a list of old column indices. collect_cols_by_key Collect values for each unique column key into arrays. cols Returns a table with all column fields in the matrix. compute_entry_filter_stats Compute statistics about the number and fraction of filtered entries. count Count the number of rows and columns in the matrix. count_cols Count the number of columns in the matrix. count_rows Count the number of rows in the matrix. describe Print information about the fields in the matrix table. distinct_by_col Remove columns with a duplicate row key, keeping exactly one column for each unique key. distinct_by_row Remove rows with a duplicate row key, keeping exactly one row for each unique key. drop Drop fields. entries Returns a matrix in coordinate table form. explode_cols Explodes a column field of type array or set, copying the entire column for each element. explode_rows Explodes a row field of type array or set, copying the entire row for each element. filter_cols Filter columns of the matrix. filter_entries Filter entries of the matrix. filter_rows Filter rows of the matrix. from_rows_table Construct matrix table with no columns from a table. globals_table Returns a table with a single row with the globals of the matrix table. group_cols_by Group columns, used with GroupedMatrixTable.aggregate(). group_rows_by Group rows, used with GroupedMatrixTable.aggregate(). head Subset matrix to first n_rows rows and n_cols cols. index_cols Expose the column values as if looked up in a dictionary, indexing with exprs. index_entries Expose the entries as if looked up in a dictionary, indexing with exprs. index_globals Return this matrix table’s global variables for use in another expression context. index_rows Expose the row values as if looked up in a dictionary, indexing with exprs. key_cols_by Key columns by a new set of fields. key_rows_by Key rows by a new set of fields. localize_entries Convert the matrix table to a table with entries localized as an array of structs. make_table Make a table from a matrix table with one field per sample. n_partitions Number of partitions. naive_coalesce Naively decrease the number of partitions. persist Persist this table in memory or on disk. rename Rename fields of a matrix table. repartition Change the number of partitions. rows Returns a table with all row fields in the matrix. sample_cols Downsample the matrix table by keeping each column with probability p. sample_rows Downsample the matrix table by keeping each row with probability p. select_cols Select existing column fields or create new fields by name, dropping the rest. select_entries Select existing entry fields or create new fields by name, dropping the rest. select_globals Select existing global fields or create new fields by name, dropping the rest. select_rows Select existing row fields or create new fields by name, dropping all other non-key fields. semi_join_cols Filters the matrix table to columns whose key appears in other. semi_join_rows Filters the matrix table to rows whose key appears in other. show Print the first few rows of the matrix table to the console. summarize Compute and print summary information about the fields in the matrix table. tail Subset matrix to last n rows. transmute_cols Similar to MatrixTable.annotate_cols(), but drops referenced fields. transmute_entries Similar to MatrixTable.annotate_entries(), but drops referenced fields. transmute_globals Similar to MatrixTable.annotate_globals(), but drops referenced fields. transmute_rows Similar to MatrixTable.annotate_rows(), but drops referenced fields. unfilter_entries Unfilters filtered entries, populating fields with missing values. union_cols Take the union of dataset columns. union_rows Take the union of dataset rows. unpersist Unpersists this dataset from memory/disk. write Write to disk.
add_col_index(name='col_idx')[source]

Add the integer index of each column as a new column field.

Examples

>>> dataset_result = dataset.add_col_index()


Notes

The field added is type tint32.

The column index is 0-indexed; the values are found in the range [0, N), where N is the total number of columns.

Parameters

name (str) – Name for column index field.

Returns

MatrixTable – Dataset with new field.

add_row_index(name='row_idx')[source]

Add the integer index of each row as a new row field.

Examples

>>> dataset_result = dataset.add_row_index()


Notes

The field added is type tint64.

The row index is 0-indexed; the values are found in the range [0, N), where N is the total number of rows.

Parameters

name (str) – Name for row index field.

Returns

MatrixTable – Dataset with new field.

aggregate_cols(expr, _localize=True)[source]

Aggregate over columns to a local value.

Examples

Aggregate over columns:

>>> dataset.aggregate_cols(
...    hl.struct(fraction_female=hl.agg.fraction(dataset.pheno.is_female),
...              case_ratio=hl.agg.count_where(dataset.is_case) / hl.agg.count()))
Struct(fraction_female=0.48, case_ratio=1.0)


Notes

Unlike most MatrixTable methods, this method does not support meaningful references to fields that are not global or indexed by column.

This method should be thought of as a more convenient alternative to the following:

>>> cols_table = dataset.cols()
>>> cols_table.aggregate(
...     hl.struct(fraction_female=hl.agg.fraction(cols_table.pheno.is_female),
...               case_ratio=hl.agg.count_where(cols_table.is_case) / hl.agg.count()))


Note

This method supports (and expects!) aggregation over columns.

Parameters

expr (Expression) – Aggregation expression.

Returns

any – Aggregated value dependent on expr.

aggregate_entries(expr, _localize=True)[source]

Aggregate over entries to a local value.

Examples

Aggregate over entries:

>>> dataset.aggregate_entries(hl.struct(global_gq_mean=hl.agg.mean(dataset.GQ),
...                                     call_rate=hl.agg.fraction(hl.is_defined(dataset.GT))))
Struct(global_gq_mean=64.01841473178543, call_rate=0.9607692307692308)


Notes

This method should be thought of as a more convenient alternative to the following:

>>> entries_table = dataset.entries()
>>> entries_table.aggregate(hl.struct(global_gq_mean=hl.agg.mean(entries_table.GQ),
...                                   call_rate=hl.agg.fraction(hl.is_defined(entries_table.GT))))


Note

This method supports (and expects!) aggregation over entries.

Parameters

expr (Expression) – Aggregation expressions.

Returns

any – Aggregated value dependent on expr.

aggregate_rows(expr, _localize=True)[source]

Aggregate over rows to a local value.

Examples

Aggregate over rows:

>>> dataset.aggregate_rows(hl.struct(n_high_quality=hl.agg.count_where(dataset.qual > 40),
...                                  mean_qual=hl.agg.mean(dataset.qual)))
Struct(n_high_quality=13, mean_qual=544323.8915384616)


Notes

Unlike most MatrixTable methods, this method does not support meaningful references to fields that are not global or indexed by row.

This method should be thought of as a more convenient alternative to the following:

>>> rows_table = dataset.rows()
>>> rows_table.aggregate(hl.struct(n_high_quality=hl.agg.count_where(rows_table.qual > 40),
...                                mean_qual=hl.agg.mean(rows_table.qual)))


Note

This method supports (and expects!) aggregation over rows.

Parameters

expr (Expression) – Aggregation expression.

Returns

any – Aggregated value dependent on expr.

annotate_cols(**named_exprs)[source]

Create new column-indexed fields by name.

Examples

Compute statistics about the GQ distribution per sample:

>>> dataset_result = dataset.annotate_cols(sample_gq_stats = hl.agg.stats(dataset.GQ))


Add sample metadata from a hail.Table.

>>> dataset_result = dataset.annotate_cols(population = s_metadata[dataset.s].pop)


Note

This method supports aggregation over rows. For instance, the usage:

>>> dataset_result = dataset.annotate_cols(mean_GQ = hl.agg.mean(dataset.GQ))


will compute the mean per column.

Notes

This method creates new column fields, but can also overwrite existing fields. Only same-scope fields can be overwritten: for example, it is not possible to annotate a global field foo and later create an column field foo. However, it would be possible to create an column field foo and later create another column field foo, overwriting the first.

The arguments to the method should either be Expression objects, or should be implicitly interpretable as expressions.

Parameters

named_exprs (keyword args of Expression) – Field names and the expressions to compute them.

Returns

MatrixTable – Matrix table with new column-indexed field(s).

annotate_entries(**named_exprs)[source]

Create new row-and-column-indexed fields by name.

Examples

Compute the allele dosage using the PL field:

>>> def get_dosage(pl):
...    # convert to linear scale
...    linear_scaled = pl.map(lambda x: 10 ** - (x / 10))
...
...    # normalize to sum to 1
...    ls_sum = hl.sum(linear_scaled)
...    linear_scaled = linear_scaled.map(lambda x: x / ls_sum)
...
...    # multiply by [0, 1, 2] and sum
...    return hl.sum(linear_scaled * [0, 1, 2])
>>>
>>> dataset_result = dataset.annotate_entries(dosage = get_dosage(dataset.PL))


Note

This method does not support aggregation.

Notes

This method creates new entry fields, but can also overwrite existing fields. Only same-scope fields can be overwritten: for example, it is not possible to annotate a global field foo and later create an entry field foo. However, it would be possible to create an entry field foo and later create another entry field foo, overwriting the first.

The arguments to the method should either be Expression objects, or should be implicitly interpretable as expressions.

Parameters

named_exprs (keyword args of Expression) – Field names and the expressions to compute them.

Returns

MatrixTable – Matrix table with new row-and-column-indexed field(s).

annotate_globals(**named_exprs)[source]

Create new global fields by name.

Examples

>>> pops_1kg = {'EUR', 'AFR', 'EAS', 'SAS', 'AMR'}
>>> dataset_result = dataset.annotate_globals(pops_in_1kg = pops_1kg,
...                                           gene_list = ['SHH', 'SCN1A', 'SPTA1', 'DISC1'])


Add global fields from another table and matrix table:

>>> dataset_result = dataset.annotate_globals(thing1 = dataset2.index_globals().global_field,


Note

This method does not support aggregation.

Notes

This method creates new global fields, but can also overwrite existing fields. Only same-scope fields can be overwritten: for example, it is not possible to annotate a row field foo and later create an global field foo. However, it would be possible to create an global field foo and later create another global field foo, overwriting the first.

The arguments to the method should either be Expression objects, or should be implicitly interpretable as expressions.

Parameters

named_exprs (keyword args of Expression) – Field names and the expressions to compute them.

Returns

MatrixTable – Matrix table with new global field(s).

annotate_rows(**named_exprs)[source]

Create new row-indexed fields by name.

Examples

Compute call statistics for high quality samples per variant:

>>> high_quality_calls = hl.agg.filter(dataset.sample_qc.gq_stats.mean > 20,
...                                    hl.agg.call_stats(dataset.GT, dataset.alleles))
>>> dataset_result = dataset.annotate_rows(call_stats = high_quality_calls)


Add functional annotations from a Table, v_metadata, and a MatrixTable, dataset2_AF, both keyed by locus and alleles.

>>> dataset_result = dataset.annotate_rows(consequence = v_metadata[dataset.locus, dataset.alleles].consequence,
...                                        dataset2_AF = dataset2.index_rows(dataset.row_key).info.AF)


Note

This method supports aggregation over columns. For instance, the usage:

>>> dataset_result = dataset.annotate_rows(mean_GQ = hl.agg.mean(dataset.GQ))


will compute the mean per row.

Notes

This method creates new row fields, but can also overwrite existing fields. Only non-key, same-scope fields can be overwritten: for example, it is not possible to annotate a global field foo and later create an row field foo. However, it would be possible to create an row field foo and later create another row field foo, overwriting the first, as long as foo is not a row key.

The arguments to the method should either be Expression objects, or should be implicitly interpretable as expressions.

Parameters

named_exprs (keyword args of Expression) – Field names and the expressions to compute them.

Returns

MatrixTable – Matrix table with new row-indexed field(s).

anti_join_cols(other)[source]

Filters the table to columns whose key does not appear in other.

Parameters

other (Table) – Table with compatible key field(s).

Returns

MatrixTable

Notes

The column key type of the matrix table must match the key type of other.

This method does not change the schema of the table; it is a method of filtering the matrix table to column keys not present in another table.

To restrict to columns whose key is present in other, use semi_join_cols().

Examples

>>> ds_result = ds.anti_join_cols(cols_to_remove)


It may be inconvenient to key the matrix table by the right-side key. In this case, it is possible to implement an anti-join using a non-key field as follows:

>>> ds_result = ds.filter_cols(hl.is_missing(cols_to_remove.index(ds['s'])))

anti_join_rows(other)[source]

Filters the table to rows whose key does not appear in other.

Parameters

other (Table) – Table with compatible key field(s).

Returns

MatrixTable

Notes

The row key type of the matrix table must match the key type of other.

This method does not change the schema of the table; it is a method of filtering the matrix table to row keys not present in another table.

To restrict to rows whose key is present in other, use semi_join_rows().

Examples

>>> ds_result = ds.anti_join_rows(rows_to_remove)


It may be expensive to key the matrix table by the right-side key. In this case, it is possible to implement an anti-join using a non-key field as follows:

>>> ds_result = ds.filter_rows(hl.is_missing(rows_to_remove.index(ds['locus'], ds['alleles'])))

cache()[source]

Persist the dataset in memory.

Examples

Persist the dataset in memory:

>>> dataset = dataset.cache()


Notes

This method is an alias for persist("MEMORY_ONLY").

Returns

MatrixTable – Cached dataset.

checkpoint(output, overwrite=False, stage_locally=False, _codec_spec=None, _read_if_exists=False, _intervals=None, _filter_intervals=False, _drop_cols=False, _drop_rows=False)[source]

Checkpoint the matrix table to disk by writing and reading using a fast, but less space-efficient codec.

Parameters
• output (str) – Path at which to write.

• stage_locally (bool) – If True, major output will be written to temporary local storage before being copied to output

• overwrite (bool) – If True, overwrite an existing file at the destination.

Returns

MatrixTable

Danger

Do not write or checkpoint to a path that is already an input source for the query. This can cause data loss.

Notes

An alias for write() followed by read_matrix_table(). It is possible to read the file at this path later with read_matrix_table(). A faster, but less efficient, codec is used or writing the data so the file will be larger than if one used write().

Examples

>>> dataset = dataset.checkpoint('output/dataset_checkpoint.mt')

choose_cols(indices)[source]

Choose a new set of columns from a list of old column indices.

Examples

Randomly shuffle column order:

>>> import random
>>> indices = list(range(dataset.count_cols()))
>>> random.shuffle(indices)
>>> dataset_reordered = dataset.choose_cols(indices)


Take the first ten columns:

>>> dataset_result = dataset.choose_cols(list(range(10)))

Parameters

indices (list of int) – List of old column indices.

Returns

MatrixTable

property col

Returns a struct expression of all column-indexed fields, including keys.

Examples

Get all column field names:

>>> list(dataset.col)
['s', 'sample_qc', 'is_case', 'pheno', 'cov', 'cov1', 'cov2', 'cohorts', 'pop']

Returns

StructExpression – Struct of all column fields.

property col_key

Column key struct.

Examples

Get the column key field names:

>>> list(dataset.col_key)
['s']

Returns

StructExpression

property col_value

Returns a struct expression including all non-key column-indexed fields.

Examples

Get all non-key column field names:

>>> list(dataset.col_value)
['sample_qc', 'is_case', 'pheno', 'cov', 'cov1', 'cov2', 'cohorts', 'pop']

Returns

StructExpression – Struct of all column fields, minus keys.

collect_cols_by_key()[source]

Collect values for each unique column key into arrays.

Examples

>>> mt = hl.utils.range_matrix_table(3, 3)
>>> col_dict = hl.literal({0: [1], 1: [2, 3], 2: [4, 5, 6]})
>>> mt = (mt.annotate_cols(foo = col_dict.get(mt.col_idx))
...     .explode_cols('foo'))
>>> mt = mt.annotate_entries(bar = mt.row_idx * mt.foo)

>>> mt.cols().show()
+---------+-------+
| col_idx |   foo |
+---------+-------+
|   int32 | int32 |
+---------+-------+
|       0 |     1 |
|       1 |     2 |
|       1 |     3 |
|       2 |     4 |
|       2 |     5 |
|       2 |     6 |
+---------+-------+

>>> mt.entries().show()
+---------+---------+-------+-------+
| row_idx | col_idx |   foo |   bar |
+---------+---------+-------+-------+
|   int32 |   int32 | int32 | int32 |
+---------+---------+-------+-------+
|       0 |       0 |     1 |     0 |
|       0 |       1 |     2 |     0 |
|       0 |       1 |     3 |     0 |
|       0 |       2 |     4 |     0 |
|       0 |       2 |     5 |     0 |
|       0 |       2 |     6 |     0 |
|       1 |       0 |     1 |     1 |
|       1 |       1 |     2 |     2 |
|       1 |       1 |     3 |     3 |
|       1 |       2 |     4 |     4 |
+---------+---------+-------+-------+
showing top 10 rows

>>> mt = mt.collect_cols_by_key()
>>> mt.cols().show()
+---------+--------------+
| col_idx | foo          |
+---------+--------------+
|   int32 | array<int32> |
+---------+--------------+
|       0 | [1]          |
|       1 | [2,3]        |
|       2 | [4,5,6]      |
+---------+--------------+

>>> mt.entries().show()
+---------+---------+--------------+--------------+
| row_idx | col_idx | foo          | bar          |
+---------+---------+--------------+--------------+
|   int32 |   int32 | array<int32> | array<int32> |
+---------+---------+--------------+--------------+
|       0 |       0 | [1]          | [0]          |
|       0 |       1 | [2,3]        | [0,0]        |
|       0 |       2 | [4,5,6]      | [0,0,0]      |
|       1 |       0 | [1]          | [1]          |
|       1 |       1 | [2,3]        | [2,3]        |
|       1 |       2 | [4,5,6]      | [4,5,6]      |
|       2 |       0 | [1]          | [2]          |
|       2 |       1 | [2,3]        | [4,6]        |
|       2 |       2 | [4,5,6]      | [8,10,12]    |
+---------+---------+--------------+--------------+


Notes

Each entry field and each non-key column field of type t is replaced by a field of type array<t>. The value of each such field is an array containing all values of that field sharing the corresponding column key. In each column, the newly collected arrays all have the same length, and the values of each pre-collection column are guaranteed to be located at the same index in their corresponding arrays.

Note

The order of the columns is not guaranteed.

Returns

MatrixTable

cols()[source]

Returns a table with all column fields in the matrix.

Examples

Extract the column table:

>>> cols_table = dataset.cols()


Warning

Matrix table columns are typically sorted by the order at import, and not necessarily by column key. Since tables are always sorted by key, the table which results from this command will have its rows sorted by the column key (which becomes the table key). To preserve the original column order as the table row order, first unkey the columns using key_cols_by() with no arguments.

Returns

Table – Table with all column fields from the matrix, with one row per column of the matrix.

compute_entry_filter_stats(row_field='entry_stats_row', col_field='entry_stats_col')[source]

Compute statistics about the number and fraction of filtered entries.

Danger

This functionality is experimental. It may not be tested as well as other parts of Hail and the interface is subject to change.

Parameters
• row_field (str) – Name for computed row field (default: entry_stats_row.

• col_field (str) – Name for computed column field (default: entry_stats_col.

Returns

MatrixTable

Notes

Adds a new row field, row_field, and a new column field, col_field, each of which are structs with the following fields:

count()[source]

Count the number of rows and columns in the matrix.

Examples

>>> dataset.count()

Returns

int, int – Number of rows, number of cols.

count_cols(_localize=True)[source]

Count the number of columns in the matrix.

Examples

Count the number of columns:

>>> n_cols = dataset.count_cols()

Returns

int – Number of columns in the matrix.

count_rows(_localize=True)[source]

Count the number of rows in the matrix.

Examples

Count the number of rows:

>>> n_rows = dataset.count_rows()

Returns

int – Number of rows in the matrix.

describe(handler=<built-in function print>, *, widget=False)[source]

Print information about the fields in the matrix table.

Note

The widget argument is experimental.

Parameters
• handler (Callable[[str], None]) – Handler function for returned string.

• widget (bool) – Create an interactive IPython widget.

distinct_by_col()[source]

Remove columns with a duplicate row key, keeping exactly one column for each unique key.

Returns

MatrixTable

distinct_by_row()[source]

Remove rows with a duplicate row key, keeping exactly one row for each unique key.

Returns

MatrixTable

drop(*exprs)[source]

Drop fields.

Examples

Drop fields PL (an entry field), info (a row field), and pheno (a column field): using strings:

>>> dataset_result = dataset.drop('PL', 'info', 'pheno')


Drop fields PL (an entry field), info (a row field), and pheno (a column field): using field references:

>>> dataset_result = dataset.drop(dataset.PL, dataset.info, dataset.pheno)


Drop a list of fields:

>>> fields_to_drop = ['PL', 'info', 'pheno']
>>> dataset_result = dataset.drop(*fields_to_drop)


Notes

This method can be used to drop global, row-indexed, column-indexed, or row-and-column-indexed (entry) fields. The arguments can be either strings ('field'), or top-level field references (table.field or table['field']).

Key fields (belonging to either the row key or the column key) cannot be dropped using this method. In order to drop a key field, use key_rows_by() or key_cols_by() to remove the field from the key before dropping.

While many operations exist independently for rows, columns, entries, and globals, only one is needed for dropping due to the lack of any necessary contextual information.

Parameters

exprs (varargs of str or Expression) – Names of fields to drop or field reference expressions.

Returns

MatrixTable – Matrix table without specified fields.

entries()[source]

Returns a matrix in coordinate table form.

Examples

Extract the entry table:

>>> entries_table = dataset.entries()


Notes

The coordinate table representation of the source matrix table contains one row for each non-filtered entry of the matrix – if a matrix table has no filtered entries and contains N rows and M columns, the table will contain M * N rows, which can be a very large number.

This representation can be useful for aggregating over both axes of a matrix table at the same time – it is not possible to aggregate over a matrix table using group_rows_by() and group_cols_by() at the same time (aggregating by population and chromosome from a variant-by-sample genetics representation, for instance). After moving to the coordinate representation with entries(), it is possible to group and aggregate the resulting table much more flexibly, albeit with potentially poorer computational performance.

Warning

The table returned by this method should be used for aggregation or queries, but never exported or written to disk without extensive filtering and field selection – the disk footprint of an entries_table could be 100x (or more!) larger than its parent matrix. This means that if you try to export the entries table of a 10 terabyte matrix, you could write a petabyte of data!

Warning

Matrix table columns are typically sorted by the order at import, and not necessarily by column key. Since tables are always sorted by key, the table which results from this command will have its rows sorted by the compound (row key, column key) which becomes the table key. To preserve the original row-major entry order as the table row order, first unkey the columns using key_cols_by() with no arguments.

Warning

If the matrix table has no row key, but has a column key, this operation may require a full shuffle to sort by the column key, depending on the pipeline.

Returns

Table – Table with all non-global fields from the matrix, with one row per entry of the matrix.

property entry

Returns a struct expression including all row-and-column-indexed fields.

Examples

Get all entry field names:

>>> list(dataset.entry)

Returns

StructExpression – Struct of all entry fields.

explode_cols(field_expr)[source]

Explodes a column field of type array or set, copying the entire column for each element.

Examples

Explode columns by annotated cohorts:

>>> dataset_result = dataset.explode_cols(dataset.cohorts)


Notes

The new matrix table will have N copies of each column, where N is the number of elements that column contains for the field denoted by field_expr. The field referenced in field_expr is replaced in the sequence of duplicated columns by the sequence of elements in the array or set. All other fields remain the same, including entry fields.

If the field referenced with field_expr is missing or empty, the column is removed entirely.

Parameters

field_expr (str or Expression) – Field name or (possibly nested) field reference expression.

Returns

MatrixTable – Matrix table exploded column-wise for each element of field_expr.

explode_rows(field_expr)[source]

Explodes a row field of type array or set, copying the entire row for each element.

Examples

Explode rows by annotated genes:

>>> dataset_result = dataset.explode_rows(dataset.gene)


Notes

The new matrix table will have N copies of each row, where N is the number of elements that row contains for the field denoted by field_expr. The field referenced in field_expr is replaced in the sequence of duplicated rows by the sequence of elements in the array or set. All other fields remain the same, including entry fields.

If the field referenced with field_expr is missing or empty, the row is removed entirely.

Parameters

field_expr (str or Expression) – Field name or (possibly nested) field reference expression.

Returns

class:MatrixTable – Matrix table exploded row-wise for each element of field_expr.

filter_cols(expr, keep=True)[source]

Filter columns of the matrix.

Examples

Keep columns where pheno.is_case is True and pheno.age is larger than 50:

>>> dataset_result = dataset.filter_cols(dataset.pheno.is_case &
...                                      (dataset.pheno.age > 50),
...                                      keep=True)


Remove columns where sample_qc.gq_stats.mean is less than 20:

>>> dataset_result = dataset.filter_cols(dataset.sample_qc.gq_stats.mean < 20,
...                                      keep=False)


Remove columns where s is found in a Python set:

>>> samples_to_remove = {'NA12878', 'NA12891', 'NA12892'}
>>> set_to_remove = hl.literal(samples_to_remove)
>>> dataset_result = dataset.filter_cols(~set_to_remove.contains(dataset['s']))


Notes

The expression expr will be evaluated for every column of the table. If keep is True, then columns where expr evaluates to True will be kept (the filter removes the columns where the predicate evaluates to False). If keep is False, then columns where expr evaluates to True will be removed (the filter keeps the columns where the predicate evaluates to False).

Warning

When expr evaluates to missing, the column will be removed regardless of keep.

Note

This method supports aggregation over rows. For instance,

>>> dataset_result = dataset.filter_cols(hl.agg.mean(dataset.GQ) > 20.0)


will remove columns where the mean GQ of all entries in the column is smaller than 20.

Parameters
Returns

MatrixTable – Filtered matrix table.

filter_entries(expr, keep=True)[source]

Filter entries of the matrix.

Parameters
Returns

MatrixTable – Filtered matrix table.

Examples

Keep entries where the sum of AD is greater than 10 and GQ is greater than 20:

>>> dataset_result = dataset.filter_entries((hl.sum(dataset.AD) > 10) & (dataset.GQ > 20))


Warning

When expr evaluates to missing, the entry will be removed regardless of keep.

Note

This method does not support aggregation.

Notes

The expression expr will be evaluated for every entry of the table. If keep is True, then entries where expr evaluates to True will be kept (the filter removes the entries where the predicate evaluates to False). If keep is False, then entries where expr evaluates to True will be removed (the filter keeps the entries where the predicate evaluates to False).

Filtered entries are removed entirely from downstream operations. This means that the resulting matrix table has sparsity – that is, that the number of entries is smaller than the product of count_rows() and count_cols(). To re-densify a filtered matrix table, use the unfilter_entries() method to restore filtered entries, populated all fields with missing values. Below are some properties of an entry-filtered matrix table.

1. Filtered entries are not included in the entries() table.

>>> mt_range = hl.utils.range_matrix_table(10, 10)
>>> mt_range = mt_range.annotate_entries(x = mt_range.row_idx + mt_range.col_idx)
>>> mt_range.count()
(10, 10)

>>> mt_range.entries().count()
100

>>> mt_filt = mt_range.filter_entries(mt_range.x % 2 == 0)
>>> mt_filt.count()
(10, 10)

>>> mt_filt.count_rows() * mt_filt.count_cols()
100

>>> mt_filt.entries().count()
50

1. Filtered entries are not included in aggregation.

>>> mt_filt.aggregate_entries(hl.agg.count())
50

>>> mt_filt = mt_filt.annotate_cols(col_n = hl.agg.count())
>>> mt_filt.col_n.take(5)
[5, 5, 5, 5, 5]

>>> mt_filt = mt_filt.annotate_rows(row_n = hl.agg.count())
>>> mt_filt.row_n.take(5)
[5, 5, 5, 5, 5]

1. Annotating a new entry field will not annotate filtered entries.

>>> mt_filt = mt_filt.annotate_entries(y = 1)
>>> mt_filt.aggregate_entries(hl.agg.sum(mt_filt.y))
50


4. If all the entries in a row or column of a matrix table are filtered, the row or column remains.

>>> mt_filt.filter_entries(False).count()
(10, 10)

filter_rows(expr, keep=True)[source]

Filter rows of the matrix.

Examples

Keep rows where variant_qc.AF is below 1%:

>>> dataset_result = dataset.filter_rows(dataset.variant_qc.AF[1] < 0.01, keep=True)


Remove rows where filters is non-empty:

>>> dataset_result = dataset.filter_rows(dataset.filters.size() > 0, keep=False)


Notes

The expression expr will be evaluated for every row of the table. If keep is True, then rows where expr evaluates to True will be kept (the filter removes the rows where the predicate evaluates to False). If keep is False, then rows where expr evaluates to True will be removed (the filter keeps the rows where the predicate evaluates to False).

Warning

When expr evaluates to missing, the row will be removed regardless of keep.

Note

This method supports aggregation over columns. For instance,

>>> dataset_result = dataset.filter_rows(hl.agg.mean(dataset.GQ) > 20.0)


will remove rows where the mean GQ of all entries in the row is smaller than 20.

Parameters
Returns

MatrixTable – Filtered matrix table.

classmethod from_rows_table(table)[source]

Construct matrix table with no columns from a table.

Danger

This functionality is experimental. It may not be tested as well as other parts of Hail and the interface is subject to change.

Examples

Import a text table and construct a rows-only matrix table:

>>> table = hl.import_table('data/variant-lof.tsv')
>>> table = table.transmute(**hl.parse_variant(table['v'])).key_by('locus', 'alleles')
>>> sites_mt = hl.MatrixTable.from_rows_table(table)


Notes

All fields in the table become row-indexed fields in the result.

Parameters

table (Table) – The table to be converted.

Returns

MatrixTable

property globals

Returns a struct expression including all global fields.

Returns

StructExpression

globals_table()[source]

Returns a table with a single row with the globals of the matrix table.

Examples

Extract the globals table:

>>> globals_table = dataset.globals_table()

Returns

Table – Table with the globals from the matrix, with a single row.

group_cols_by(*exprs, **named_exprs)[source]

Group columns, used with GroupedMatrixTable.aggregate().

Examples

Aggregate to a matrix with cohort as column keys, computing the call rate as an entry field:

>>> dataset_result = (dataset.group_cols_by(dataset.cohort)
...                          .aggregate(call_rate = hl.agg.fraction(hl.is_defined(dataset.GT))))


Notes

All complex expressions must be passed as named expressions.

Parameters
Returns

GroupedMatrixTable – Grouped matrix, can be used to call GroupedMatrixTable.aggregate().

group_rows_by(*exprs, **named_exprs)[source]

Group rows, used with GroupedMatrixTable.aggregate().

Examples

Aggregate to a matrix with genes as row keys, computing the number of non-reference calls as an entry field:

>>> dataset_result = (dataset.group_rows_by(dataset.gene)
...                          .aggregate(n_non_ref = hl.agg.count_where(dataset.GT.is_non_ref())))


Notes

All complex expressions must be passed as named expressions.

Parameters
Returns

GroupedMatrixTable – Grouped matrix. Can be used to call GroupedMatrixTable.aggregate().

head(n_rows, n_cols=None, *, n=None)[source]

Subset matrix to first n_rows rows and n_cols cols.

Examples

>>> mt_range = hl.utils.range_matrix_table(100, 100)


Passing only one argument will take the first n_rows rows:

>>> mt_range.head(10).count()
(10, 100)


Passing two arguments refers to rows and columns, respectively:

>>> mt_range.head(10, 20).count()
(10, 20)


Either argument may be None to indicate no filter.

First 10 rows, all columns:

>>> mt_range.head(10, None).count()
(10, 100)


All rows, first 10 columns:

>>> mt_range.head(None, 10).count()
(100, 10)


Notes

The number of partitions in the new matrix is equal to the number of partitions containing the first n_rows rows.

Parameters
• n_rows (int) – Number of rows to include (all rows included if None).

• n_cols (int, optional) – Number of cols to include (all cols included if None).

• n (int) – Deprecated in favor of n_rows.

Returns

MatrixTable – Matrix including the first n_rows rows and first n_cols cols.

index_cols(*exprs, all_matches=False)[source]

Expose the column values as if looked up in a dictionary, indexing with exprs.

Examples

>>> dataset_result = dataset.annotate_cols(pheno = dataset2.index_cols(dataset.s).pheno)


Or equivalently:

>>> dataset_result = dataset.annotate_cols(pheno = dataset2.index_cols(dataset.col_key).pheno)

Parameters
• exprs (variable-length args of Expression) – Index expressions.

• all_matches (bool) – Experimental. If True, value of expression is array of all matches.

Notes

index_cols(cols) is equivalent to cols().index(exprs) or cols()[exprs].

The type of the resulting struct is the same as the type of col_value().

Returns

Expression

index_entries(row_exprs, col_exprs)[source]

Expose the entries as if looked up in a dictionary, indexing with exprs.

Examples

>>> dataset_result = dataset.annotate_entries(GQ2 = dataset2.index_entries(dataset.row_key, dataset.col_key).GQ)


Or equivalently:

>>> dataset_result = dataset.annotate_entries(GQ2 = dataset2[dataset.row_key, dataset.col_key].GQ)

Parameters

Notes

The type of the resulting struct is the same as the type of entry().

Note

There is a shorthand syntax for MatrixTable.index_entries() using square brackets (the Python __getitem__ syntax). This syntax is preferred.

>>> dataset_result = dataset.annotate_entries(GQ2 = dataset2[dataset.row_key, dataset.col_key].GQ)

Returns

StructExpression

index_globals()[source]

Return this matrix table’s global variables for use in another expression context.

Examples

>>> dataset1 = dataset.annotate_globals(pli={'SCN1A': 0.999, 'SONIC': 0.014})
>>> pli_dict = dataset1.index_globals().pli
>>> dataset_result = dataset2.annotate_rows(gene_pli = dataset2.gene.map(lambda x: pli_dict.get(x)))

Returns

StructExpression

index_rows(*exprs, all_matches=False)[source]

Expose the row values as if looked up in a dictionary, indexing with exprs.

Examples

>>> dataset_result = dataset.annotate_rows(qual = dataset2.index_rows(dataset.locus, dataset.alleles).qual)


Or equivalently:

>>> dataset_result = dataset.annotate_rows(qual = dataset2.index_rows(dataset.row_key).qual)

Parameters
• exprs (variable-length args of Expression) – Index expressions.

• all_matches (bool) – Experimental. If True, value of expression is array of all matches.

Notes

index_rows(exprs) is equivalent to rows().index(exprs) or rows()[exprs].

The type of the resulting struct is the same as the type of row_value().

Returns

Expression

key_cols_by(*keys, **named_keys)[source]

Key columns by a new set of fields.

See Table.key_by() for more information on defining a key.

Parameters
Returns

MatrixTable

key_rows_by(*keys, **named_keys)[source]

Key rows by a new set of fields.

Examples

>>> dataset_result = dataset.key_rows_by('locus')
>>> dataset_result = dataset.key_rows_by(dataset['locus'])
>>> dataset_result = dataset.key_rows_by(**dataset.row_key.drop('alleles'))


All of these expressions key the dataset by the ‘locus’ field, dropping the ‘alleles’ field from the row key.

>>> dataset_result = dataset.key_rows_by(contig=dataset['locus'].contig,
...                                      position=dataset['locus'].position,
...                                      alleles=dataset['alleles'])


This keys the dataset by the newly defined fields, ‘contig’ and ‘position’, and the ‘alleles’ field. The old row key field, ‘locus’, is preserved as a non-key field.

Notes

See Table.key_by() for more information on defining a key.

Parameters
Returns

MatrixTable

localize_entries(entries_array_field_name=None, columns_array_field_name=None)[source]

Convert the matrix table to a table with entries localized as an array of structs.

Examples

Build a numpy ndarray from a small MatrixTable:

>>> mt = hl.utils.range_matrix_table(3,3)
>>> mt = mt.select_entries(x = mt.row_idx * mt.col_idx)
>>> mt.show()
+---------+-------+-------+-------+
| row_idx |   0.x |   1.x |   2.x |
+---------+-------+-------+-------+
|   int32 | int32 | int32 | int32 |
+---------+-------+-------+-------+
|       0 |     0 |     0 |     0 |
|       1 |     0 |     1 |     2 |
|       2 |     0 |     2 |     4 |
+---------+-------+-------+-------+

>>> t = mt.localize_entries('entry_structs', 'columns')
>>> t.describe()
----------------------------------------
Global fields:
'columns': array<struct {
col_idx: int32
}>
----------------------------------------
Row fields:
'row_idx': int32
'entry_structs': array<struct {
x: int32
}>
----------------------------------------
Key: ['row_idx']
----------------------------------------

>>> t = t.select(entries = t.entry_structs.map(lambda entry: entry.x))
>>> import numpy as np
>>> np.array(t.entries.collect())
array([[0, 0, 0],
[0, 1, 2],
[0, 2, 4]])


Notes

Both of the added fields are arrays of length equal to mt.count_cols(). Missing entries are represented as missing structs in the entries array.

Parameters
• entries_array_field_name (str) – The name of the table field containing the array of entry structs for the given row.

• columns_array_field_name (str) – The name of the global field containing the array of column structs.

Returns

Table – A table whose fields are the row fields of this matrix table plus one field named entries_array_field_name. The global fields of this table are the global fields of this matrix table plus one field named columns_array_field_name.

make_table(separator='.')[source]

Make a table from a matrix table with one field per sample.

Examples

Consider a matrix table with the following schema:

Global fields:
'batch': str
Column fields:
's': str
Row fields:
'locus': locus<GRCh37>
'alleles': array<str>
Entry fields:
'GT': call
'GQ': int32
Column key:
's': str
Row key:
'locus': locus<GRCh37>
'alleles': array<str>


and three sample IDs: A, B and C. Then the result of make_table():

>>> ht = mt.make_table()


has the original row fields along with 6 additional fields, one for each sample and entry field:

Global fields:
'batch': str
Row fields:
'locus': locus<GRCh37>
'alleles': array<str>
'A.GT': call
'A.GQ': int32
'B.GT': call
'B.GQ': int32
'C.GT': call
'C.GQ': int32
Key:
'locus': locus<GRCh37>
'alleles': array<str>


Notes

The table has one row for each row of the input matrix. The per sample and entry fields are formed by concatenating the sample ID with the entry field name using separator. If the entry field name is empty, the separator is omitted.

The table inherits the globals from the matrix table.

Parameters

separator (str) – Separator between sample IDs and entry field names.

Returns

Table

n_partitions()[source]

Number of partitions.

Notes

The data in a dataset is divided into chunks called partitions, which may be stored together or across a network, so that each partition may be read and processed in parallel by available cores. Partitions are a core concept of distributed computation in Spark, see here for details.

Returns

int – Number of partitions.

naive_coalesce(max_partitions)[source]

Naively decrease the number of partitions.

Example

Naively repartition to 10 partitions:

>>> dataset_result = dataset.naive_coalesce(10)


Warning

naive_coalesce() simply combines adjacent partitions to achieve the desired number. It does not attempt to rebalance, unlike repartition(), so it can produce a heavily unbalanced dataset. An unbalanced dataset can be inefficient to operate on because the work is not evenly distributed across partitions.

Parameters

max_partitions (int) – Desired number of partitions. If the current number of partitions is less than or equal to max_partitions, do nothing.

Returns

MatrixTable – Matrix table with at most max_partitions partitions.

persist(storage_level='MEMORY_AND_DISK')[source]

Persist this table in memory or on disk.

Examples

Persist the dataset to both memory and disk:

>>> dataset = dataset.persist()


Notes

The MatrixTable.persist() and MatrixTable.cache() methods store the current dataset on disk or in memory temporarily to avoid redundant computation and improve the performance of Hail pipelines. This method is not a substitution for Table.write(), which stores a permanent file.

Most users should use the “MEMORY_AND_DISK” storage level. See the Spark documentation for a more in-depth discussion of persisting data.

Parameters

storage_level (str) – Storage level. One of: NONE, DISK_ONLY, DISK_ONLY_2, MEMORY_ONLY, MEMORY_ONLY_2, MEMORY_ONLY_SER, MEMORY_ONLY_SER_2, MEMORY_AND_DISK, MEMORY_AND_DISK_2, MEMORY_AND_DISK_SER, MEMORY_AND_DISK_SER_2, OFF_HEAP

Returns

MatrixTable – Persisted dataset.

rename(fields)[source]

Rename fields of a matrix table.

Examples

Rename column key s to SampleID, still keying by SampleID.

>>> dataset_result = dataset.rename({'s': 'SampleID'})


You can rename a field to a field name that already exists, as long as that field also gets renamed (no name collisions). Here, we rename the column key s to info, and the row field info to vcf_info:

>>> dataset_result = dataset.rename({'s': 'info', 'info': 'vcf_info'})

Parameters

fields (dict from str to str) – Mapping from old field names to new field names.

Returns

MatrixTable – Matrix table with renamed fields.

repartition(n_partitions, shuffle=True)[source]

Change the number of partitions.

Examples

Repartition to 500 partitions:

>>> dataset_result = dataset.repartition(500)


Notes

Check the current number of partitions with n_partitions().

The data in a dataset is divided into chunks called partitions, which may be stored together or across a network, so that each partition may be read and processed in parallel by available cores. When a matrix with $$M$$ rows is first imported, each of the $$k$$ partitions will contain about $$M/k$$ of the rows. Since each partition has some computational overhead, decreasing the number of partitions can improve performance after significant filtering. Since it’s recommended to have at least 2 - 4 partitions per core, increasing the number of partitions can allow one to take advantage of more cores. Partitions are a core concept of distributed computation in Spark, see their documentation for details.

When shuffle=True, Hail does a full shuffle of the data and creates equal sized partitions. When shuffle=False, Hail combines existing partitions to avoid a full shuffle. These algorithms correspond to the repartition and coalesce commands in Spark, respectively. In particular, when shuffle=False, n_partitions cannot exceed current number of partitions.

Parameters
• n_partitions (int) – Desired number of partitions.

• shuffle (bool) – If True, use full shuffle to repartition.

Returns

MatrixTable – Repartitioned dataset.

property row

Returns a struct expression of all row-indexed fields, including keys.

Examples

Get the first five row field names:

>>> list(dataset.row)[:5]
['locus', 'alleles', 'rsid', 'qual', 'filters']

Returns

StructExpression – Struct of all row fields.

property row_key

Row key struct.

Examples

Get the row key field names:

>>> list(dataset.row_key)
['locus', 'alleles']

Returns

StructExpression

property row_value

Returns a struct expression including all non-key row-indexed fields.

Examples

Get the first five non-key row field names:

>>> list(dataset.row_value)[:5]
['rsid', 'qual', 'filters', 'info', 'use_as_marker']

Returns

StructExpression – Struct of all row fields, minus keys.

rows()[source]

Returns a table with all row fields in the matrix.

Examples

Extract the row table:

>>> rows_table = dataset.rows()

Returns

Table – Table with all row fields from the matrix, with one row per row of the matrix.

sample_cols(p, seed=None)[source]

Downsample the matrix table by keeping each column with probability p.

Examples

Downsample the dataset to approximately 1% of its columns.

>>> small_dataset = dataset.sample_cols(0.01)

Parameters
Returns

MatrixTable – Matrix table with approximately p * n_cols column.

sample_rows(p, seed=None)[source]

Downsample the matrix table by keeping each row with probability p.

Examples

Downsample the dataset to approximately 1% of its rows.

>>> small_dataset = dataset.sample_rows(0.01)


Notes

Although the MatrixTable returned by this method may be small, it requires a full pass over the rows of the sampled object.

Parameters
Returns

MatrixTable – Matrix table with approximately p * n_rows rows.

select_cols(*exprs, **named_exprs)[source]

Select existing column fields or create new fields by name, dropping the rest.

Examples

Select existing fields and compute a new one:

>>> dataset_result = dataset.select_cols(
...     dataset.sample_qc,
...     dataset.pheno.age,
...     isCohort1 = dataset.pheno.cohort_name == 'Cohort1')


Notes

This method creates new column fields. If a created field shares its name with a differently-indexed field of the table, the method will fail.

Note

See Table.select() for more information about using select methods.

Note

This method supports aggregation over rows. For instance, the usage:

>>> dataset_result = dataset.select_cols(mean_GQ = hl.agg.mean(dataset.GQ))


will compute the mean per column.

Parameters
Returns

MatrixTable – MatrixTable with specified column fields.

select_entries(*exprs, **named_exprs)[source]

Select existing entry fields or create new fields by name, dropping the rest.

Examples

Drop all entry fields aside from GT:

>>> dataset_result = dataset.select_entries(dataset.GT)


Notes

This method creates new entry fields. If a created field shares its name with a differently-indexed field of the table, the method will fail.

Note

See Table.select() for more information about using select methods.

Note

This method does not support aggregation.

Parameters
Returns

MatrixTable – MatrixTable with specified entry fields.

select_globals(*exprs, **named_exprs)[source]

Select existing global fields or create new fields by name, dropping the rest.

Examples

Select one existing field and compute a new one:

>>> dataset_result = dataset.select_globals(dataset.global_field_1,
...                                         another_global=['AFR', 'EUR', 'EAS', 'AMR', 'SAS'])


Notes

This method creates new global fields. If a created field shares its name with a differently-indexed field of the table, the method will fail.

Note

See Table.select() for more information about using select methods.

Note

This method does not support aggregation.

Parameters
Returns

MatrixTable – MatrixTable with specified global fields.

select_rows(*exprs, **named_exprs)[source]

Select existing row fields or create new fields by name, dropping all other non-key fields.

Examples

Select existing fields and compute a new one:

>>> dataset_result = dataset.select_rows(
...    dataset.variant_qc.gq_stats.mean,
...    high_quality_cases = hl.agg.count_where((dataset.GQ > 20) &
...                                         dataset.is_case))


Notes

This method creates new row fields. If a created field shares its name with a differently-indexed field of the table, or with a row key, the method will fail.

Row keys are preserved. To drop or change a row key field, use MatrixTable.key_rows_by().

Note

See Table.select() for more information about using select methods.

Note

This method supports aggregation over columns. For instance, the usage:

>>> dataset_result = dataset.select_rows(mean_GQ = hl.agg.mean(dataset.GQ))


will compute the mean per row.

Parameters
Returns

MatrixTable – MatrixTable with specified row fields.

semi_join_cols(other)[source]

Filters the matrix table to columns whose key appears in other.

Parameters

other (Table) – Table with compatible key field(s).

Returns

MatrixTable

Notes

The column key type of the matrix table must match the key type of other.

This method does not change the schema of the matrix table; it is a filtering the matrix table to column keys not present in another table.

To discard collumns whose key is present in other, use anti_join_cols().

Examples

>>> ds_result = ds.semi_join_cols(cols_to_keep)


It may be inconvenient to key the matrix table by the right-side key. In this case, it is possible to implement a semi-join using a non-key field as follows:

>>> ds_result = ds.filter_cols(hl.is_defined(cols_to_keep.index(ds['s'])))

semi_join_rows(other)[source]

Filters the matrix table to rows whose key appears in other.

Parameters

other (Table) – Table with compatible key field(s).

Returns

MatrixTable

Notes

The row key type of the matrix table must match the key type of other.

This method does not change the schema of the matrix table; it is filtering the matrix table to row keys present in another table.

To discard rows whose key is present in other, use anti_join_rows().

Examples

>>> ds_result = ds.semi_join_rows(rows_to_keep)


It may be expensive to key the matrix table by the right-side key. In this case, it is possible to implement a semi-join using a non-key field as follows:

>>> ds_result = ds.filter_rows(hl.is_defined(rows_to_keep.index(ds['locus'], ds['alleles'])))

show(n_rows=None, n_cols=None, include_row_fields=False, width=None, truncate=None, types=True, handler=None)[source]

Print the first few rows of the matrix table to the console.

Danger

This functionality is experimental. It may not be tested as well as other parts of Hail and the interface is subject to change.

Notes

The output can be passed piped to another output source using the handler argument:

>>> mt.show(handler=lambda x: logging.info(x))

Parameters
• n_rows (int) – Maximum number of rows to show.

• n_cols (int) – Maximum number of columns to show.

• width (int) – Horizontal width at which to break fields.

• truncate (int, optional) – Truncate each field to the given number of characters. If None, truncate fields to the given width.

• types (bool) – Print an extra header line with the type of each field.

• handler (Callable[[str], Any]) – Handler function for data string.

summarize(*, rows=True, cols=True, entries=True, handler=None)[source]

Compute and print summary information about the fields in the matrix table.

Danger

This functionality is experimental. It may not be tested as well as other parts of Hail and the interface is subject to change.

Parameters
tail(n, n_cols=None)[source]

Subset matrix to last n rows.

Examples

>>> mt_range = hl.utils.range_matrix_table(100, 100)


Passing only one argument will take the last n rows:

>>> mt_range.tail(10).count()
(10, 100)


Passing two arguments refers to rows and columns, respectively:

>>> mt_range.tail(10, 20).count()
(10, 20)


Either argument may be None to indicate no filter.

Last 10 rows, all columns:

>>> mt_range.tail(10, None).count()
(10, 100)


All rows, last 10 columns:

>>> mt_range.tail(None, 10).count()
(100, 10)


Notes

For backwards compatibility, the n parameter is not named n_rows, but the parameter refers to the number of rows to keep.

The number of partitions in the new matrix is equal to the number of partitions containing the last n rows.

Parameters
• n (int) – Number of rows to include (all rows included if None).

• n_cols (int, optional) – Number of cols to include (all cols included if None).

Returns

MatrixTable – Matrix including the last n rows and last n_cols cols.

transmute_cols(**named_exprs)[source]

Similar to MatrixTable.annotate_cols(), but drops referenced fields.

Notes

This method adds new column fields according to named_exprs, and drops all column fields referenced in those expressions. See Table.transmute() for full documentation on how transmute methods work.

Note

transmute_cols() will not drop key fields.

Note

This method supports aggregation over rows.

Parameters

named_exprs (keyword args of Expression) – Annotation expressions.

Returns

MatrixTable

transmute_entries(**named_exprs)[source]

Similar to MatrixTable.annotate_entries(), but drops referenced fields.

Notes

This method adds new entry fields according to named_exprs, and drops all entry fields referenced in those expressions. See Table.transmute() for full documentation on how transmute methods work.

Parameters

named_exprs (keyword args of Expression) – Annotation expressions.

Returns

MatrixTable

transmute_globals(**named_exprs)[source]

Similar to MatrixTable.annotate_globals(), but drops referenced fields.

Notes

This method adds new global fields according to named_exprs, and drops all global fields referenced in those expressions. See Table.transmute() for full documentation on how transmute methods work.

Parameters

named_exprs (keyword args of Expression) – Annotation expressions.

Returns

MatrixTable

transmute_rows(**named_exprs)[source]

Similar to MatrixTable.annotate_rows(), but drops referenced fields.

Notes

This method adds new row fields according to named_exprs, and drops all row fields referenced in those expressions. See Table.transmute() for full documentation on how transmute methods work.

Note

transmute_rows() will not drop key fields.

Note

This method supports aggregation over columns.

Parameters

named_exprs (keyword args of Expression) – Annotation expressions.

Returns

MatrixTable

unfilter_entries()[source]

Unfilters filtered entries, populating fields with missing values.

Returns

MatrixTable

Notes

This method is used in the case that a pipeline downstream of filter_entries() requires a fully dense (no filtered entries) matrix table.

Generally, if this method is required in a pipeline, the upstream pipeline can be rewritten to use annotation instead of entry filtering.

union_cols(other, row_join_type='inner')[source]

Take the union of dataset columns.

Examples

Union the columns of two datasets:

>>> dataset_result = dataset_to_union_1.union_cols(dataset_to_union_2)


Notes

In order to combine two datasets, three requirements must be met:

• The row keys must match.

• The column key schemas and column schemas must match.

• The entry schemas must match.

The row fields in the resulting dataset are the row fields from the first dataset; the row schemas do not need to match.

This method creates a MatrixTable which contains all columns from both input datasets. The set of rows included in the result is determined by the row_join_type parameter.

• With the default value of 'inner', an inner join is performed on rows, so that only rows whose row key exists in both input datasets are included. In this case, the entries for each row are the concatenation of all entries of the corresponding rows in the input datasets.

• With row_join_type set to 'outer', an outer join is perfomed on rows, so that row keys which exist in only one input dataset are also included. For those rows, the entry fields for the columns coming from the other dataset will be missing.

Only distinct row keys from each dataset are included (equivalent to calling distinct_by_row() on each dataset first).

This method does not deduplicate; if a column key exists identically in two datasets, then it will be duplicated in the result.

Parameters
• other (MatrixTable) – Dataset to concatenate.

• outer (bool) – If True, perform an outer join on rows, otherwise perform an inner join. Default False.

Returns

MatrixTable – Dataset with columns from both datasets.

union_rows(*, _check_cols=True)[source]

Take the union of dataset rows.

Examples

Union the rows of two datasets:

>>> dataset_result = dataset_to_union_1.union_rows(dataset_to_union_2)


Given a list of datasets, take the union of all rows:

>>> all_datasets = [dataset_to_union_1, dataset_to_union_2]


The following three syntaxes are equivalent:

>>> dataset_result = dataset_to_union_1.union_rows(dataset_to_union_2)
>>> dataset_result = all_datasets[0].union_rows(*all_datasets[1:])
>>> dataset_result = hl.MatrixTable.union_rows(*all_datasets)


Notes

In order to combine two datasets, three requirements must be met:

• The column keys must be identical, both in type, value, and ordering.

• The row key schemas and row schemas must match.

• The entry schemas must match.

The column fields in the resulting dataset are the column fields from the first dataset; the column schemas do not need to match.

This method does not deduplicate; if a row exists identically in two datasets, then it will be duplicated in the result.

Warning

This method can trigger a shuffle, if partitions from two datasets overlap.

Parameters

datasets (varargs of MatrixTable) – Datasets to combine.

Returns

MatrixTable – Dataset with rows from each member of datasets.

unpersist()[source]

Unpersists this dataset from memory/disk.

Notes

This function will have no effect on a dataset that was not previously persisted.

Returns

MatrixTable – Unpersisted dataset.

write(output, overwrite=False, stage_locally=False, _codec_spec=None, _partitions=None, _checkpoint_file=None)[source]

Write to disk.

Examples

>>> dataset.write('output/dataset.mt')


Danger

Do not write or checkpoint to a path that is already an input source for the query. This can cause data loss.

Parameters
• output (str) – Path at which to write.

• stage_locally (bool) – If True, major output will be written to temporary local storage before being copied to output

• overwrite (bool) – If True`, overwrite an existing file at the destination.