SwitchBuilder

class hail.expr.builders.SwitchBuilder[source]

Class for generating conditional trees based on value of an expression.

Examples

>>> csq = hl.literal('loss of function')
>>> expr = (hl.switch(csq)
...           .when('synonymous', 1)
...           .when('SYN', 1)
...           .when('missense', 2)
...           .when('MIS', 2)
...           .when('loss of function', 3)
...           .when('LOF', 3)
...           .or_missing())
>>> hl.eval(expr)
3

Notes

All expressions appearing as the then parameters to when() or default() method calls must be the same type.

See also

case(), cond(), switch()

Parameters:: expr (Expression) – Value to match against.

Attributes

Methods

`default`	Finish the switch statement by adding a default case.
`or_error`	Finish the switch statement by throwing an error with the given message.
`or_missing`	Finish the switch statement by returning missing.
`when`	Add a value test.
`when_missing`	Add a test for missingness.

default(then)[source]

Finish the switch statement by adding a default case.

Notes

If no value from a when() call is matched, then then is returned.

Parameters:: then (Expression)
Returns:: Expression

or_error(message)[source]

Finish the switch statement by throwing an error with the given message.

Notes

If no value from a SwitchBuilder.when() call is matched, then an error is thrown.

Parameters:: message (Expression of type tstr)
Returns:: Expression

or_missing()[source]

Finish the switch statement by returning missing.

Notes

If no value from a when() call is matched, then the result is missing.

Parameters:: then (Expression)
Returns:: Expression

when(value, then)[source]

Add a value test. If the base expression is equal to value, then returns then.

Warning

Missingness always compares to missing. Both NA == NA and NA != NA return NA. Use when_missing() to test missingness.

Parameters:

value (Expression)
then (Expression)

Returns:

SwitchBuilder – Mutates and returns self.

when_missing(then)[source]

Add a test for missingness. If the base expression is missing, returns then.

Parameters:: then (Expression)
Returns:: SwitchBuilder – Mutates and returns self.