maxframe.liteframe.LiteFrame.case_when

LiteFrame.case_when(caselist)

Replace values where conditions are True, evaluated in order.

Mirrors pandas.Series.case_when: each (cond, replacement) pair is evaluated sequentially; the first condition that is True determines the replacement value for that row. Rows where no condition is True keep their original value.

Both cond and replacement may be callables; when callable they are invoked with lf and should return a LiteFrame (for cond) or a LiteFrame / scalar (for replacement), matching the pandas contract where callables are computed on the Series itself.

Parameters:

caselist (list of (condition, replacement)) – Ordered list of (condition, replacement) pairs. condition is a boolean LiteFrame, or a callable returning one. replacement is a scalar, a LiteFrame, or a callable returning either.

Returns:

A LiteFrame with the same columns as lf.

Return type:

LiteFrame

See also

where

Replace values where a condition is False.

mask

Replace values where a condition is True.

Examples

>>> import maxframe.liteframe as mlf
>>> lf = mlf.LiteFrame({'a': [1, 2, 3, 4]})
>>> result = lf.case_when([(lf < 2, 0), (lf > 3, 10)])
>>> result.execute()
    a
0   0
1   2
2   3
3  10