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pandas.DataFrame.transformΒΆ

DataFrame.transform(func, *args, **kwargs)[source]ΒΆ

Call function producing a like-indexed NDFrame and return a NDFrame with the transformed values`

New in version 0.20.0.

Parameters:

func : callable, string, dictionary, or list of string/callables

To apply to column

Accepted Combinations are:

  • string function name
  • function
  • list of functions
  • dict of column names -> functions (or list of functions)
Returns:

transformed : NDFrame

See also

pandas.NDFrame.aggregate, pandas.NDFrame.apply

Examples

>>> df = pd.DataFrame(np.random.randn(10, 3), columns=['A', 'B', 'C'],
...                   index=pd.date_range('1/1/2000', periods=10))
df.iloc[3:7] = np.nan
>>> df.transform(lambda x: (x - x.mean()) / x.std())
                   A         B         C
2000-01-01  0.579457  1.236184  0.123424
2000-01-02  0.370357 -0.605875 -1.231325
2000-01-03  1.455756 -0.277446  0.288967
2000-01-04       NaN       NaN       NaN
2000-01-05       NaN       NaN       NaN
2000-01-06       NaN       NaN       NaN
2000-01-07       NaN       NaN       NaN
2000-01-08 -0.498658  1.274522  1.642524
2000-01-09 -0.540524 -1.012676 -0.828968
2000-01-10 -1.366388 -0.614710  0.005378
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