bff.log_df

bff.log_df(df, f=<function <lambda>>, msg='')

Log information on a DataFrame before returning it.

The given function is applied and the result is printed. The original DataFrame is returned, unmodified.

This allows printing debug information in method chaining.

Parameters

• df (pd.DataFrame) – DataFrame to log.

• f (Callable, default is the shape of the DataFrame) – Function to apply on the DataFrame and to log.

Returns

The DataFrame, unmodified.

Return type

pd.DataFrame

Examples

>>> import pandas as pd
>>> import pandas.util.testing as tm
>>> df = tm.makeDataFrame().head()
>>> df_res = (df.pipe(log_df)
...           .assign(E=2)
...           .pipe(log_df, f=lambda x: x.head(), msg='My df: \n')
...           .pipe(log_df, lambda x: x.shape, 'New shape=')
...          )
2019-11-04 13:31:34,742 [INFO   ] bff.fancy: (5, 4)
2019-11-04 13:31:34,758 [INFO   ] bff.fancy: My df:
                   A         B         C         D  E
7t93kTGSqJ -0.104845 -1.296579 -0.487572  0.928964  2
P8CEEHf07x -0.462075 -2.426990 -0.538038  0.487148  2
0DlwZOOj83 -1.964108 -1.272991  0.622618 -0.562890  2
LcrsmbFAjk -0.827403 -0.015269 -0.970148  0.683915  2
kHfxaURF8t  0.654381  0.353666 -0.830602  1.788581  2
2019-11-04 13:31:34,758 [INFO   ] bff.fancy: New shape=(5, 5)