Allow .where to accept callable as condition

[sinhrks]

Code Sample, a copy-pastable example if possible

Allow .where and .mask to accept callable as cond. This is useful if DataFrame is changed during method chaining.

df = pd.DataFrame(np.random.randn(2, 2))
df.where(lambda x: x > 0)
# currently raises ValueError

Expected Output

Should be the same as:

df.where(df > 0)
#           0         1
#0  0.689202       NaN
#1       NaN  0.261644

[jreback]

yeah I link to the master issue for this #11485; .query, .where, and indexers should accept callables