Source code for hail.utils.struct

from collections import OrderedDict
from import Mapping
import pprint

from hail.utils.misc import get_nice_attr_error, get_nice_field_error
from hail.typecheck import typecheck, typecheck_method, anytype

[docs]class Struct(Mapping): """ Nested annotation structure. >>> bar = hl.Struct(**{'foo': 5, '1kg': 10}) Struct elements are treated as both 'items' and 'attributes', which allows either syntax for accessing the element "foo" of struct "bar": >>> >>> bar['foo'] Field names that are not valid Python identifiers, such as fields that start with numbers or contain spaces, must be accessed with the latter syntax: >>> bar['1kg'] The ``pprint`` module can be used to print nested Structs in a more human-readable fashion: >>> from pprint import pprint >>> pprint(bar) Parameters ---------- attributes Field names and values. Note ---- This object refers to the Python value returned by taking or collecting Hail expressions, e.g. ````. This is rare; it is much more common to manipulate the :class:`.StructExpression` object, which is constructed using the :func:`.struct` function. """ def __init__(self, **kwargs): # Set this way to avoid an infinite recursion in `__getattr__`. self.__dict__["_fields"] = kwargs def __contains__(self, item): return item in self._fields def _get_field(self, item): if item in self._fields: return self._fields[item] else: raise KeyError(get_nice_field_error(self, item)) @typecheck_method(item=str) def __getitem__(self, item): return self._get_field(item) def __setattr__(self, key, value): if key in self._fields: raise ValueError("Structs are immutable, cannot overwrite a field.") else: super().__setattr__(key, value) def __getattr__(self, item): if item in self.__dict__: return self.__dict__[item] elif item in self._fields: return self._fields[item] else: raise AttributeError(get_nice_attr_error(self, item)) def __len__(self): return len(self._fields) def __repr__(self): return str(self) def __str__(self): return 'Struct({})'.format(', '.join('{}={}'.format(k, repr(v)) for k, v in self._fields.items())) def __eq__(self, other): return isinstance(other, Struct) and self._fields == other._fields def __hash__(self): return 37 + hash(tuple(sorted(self._fields.items()))) def __iter__(self): return iter(self._fields) def __dir__(self): super_dir = super().__dir__() return super_dir + list(self._fields.keys()) def annotate(self, **kwargs): """Add new fields or recompute existing fields. Notes ----- If an expression in `kwargs` shares a name with a field of the struct, then that field will be replaced but keep its position in the struct. New fields will be appended to the end of the struct. Parameters ---------- kwargs : keyword args Fields to add. Returns ------- :class:`.Struct` Struct with new or updated fields. """ d = OrderedDict(self.items()) for k, v in kwargs.items(): d[k] = v return Struct(**d) @typecheck_method(fields=str, kwargs=anytype) def select(self, *fields, **kwargs): """Select existing fields and compute new ones. Notes ----- The `fields` argument is a list of field names to keep. These fields will appear in the resulting struct in the order they appear in `fields`. The `kwargs` arguments are new fields to add. Parameters ---------- fields : varargs of :class:`str` Field names to keep. named_exprs : keyword args New field. Returns ------- :class:`.Struct` Struct containing specified existing fields and computed fields. """ d = OrderedDict() for a in fields: d[a] = self[a] for k, v in kwargs.items(): if k in d: raise ValueError("Cannot select and assign field '{}' in the same statement".format(k)) d[k] = v return Struct(**d) @typecheck_method(args=str) def drop(self, *args): """Drop fields from the struct. Parameters ---------- fields: varargs of :class:`str` Fields to drop. Returns ------- :class:`.Struct` Struct without certain fields. """ d = OrderedDict((k, v) for k, v in self.items() if k not in args) return Struct(**d)
@typecheck(struct=Struct) def to_dict(struct): return dict(struct.items()) _old_printer = pprint.PrettyPrinter class StructPrettyPrinter(pprint.PrettyPrinter): def _format(self, obj, *args, **kwargs): if isinstance(obj, Struct): obj = to_dict(obj) return _old_printer._format(self, obj, *args, **kwargs) pprint.PrettyPrinter = StructPrettyPrinter # monkey-patch pprint