pandas.core.groupby.GroupBy.pipe — pandas 0.24.0rc1 documentation (original) (raw)
GroupBy. pipe(func, *args, **kwargs)[source]¶
Apply a function func with arguments to this GroupBy object and return the function’s result.
New in version 0.21.0.
Use .pipe when you want to improve readability by chaining together functions that expect Series, DataFrames, GroupBy or Resampler objects. Instead of writing
h(g(f(df.groupby('group')), arg1=a), arg2=b, arg3=c)
You can write
(df.groupby('group') ... .pipe(f) ... .pipe(g, arg1=a) ... .pipe(h, arg2=b, arg3=c))
which is much more readable.
| Parameters: | func : callable or tuple of (callable, string) Function to apply to this GroupBy object or, alternatively, a (callable, data_keyword) tuple where data_keyword is a string indicating the keyword of callable that expects the GroupBy object. args : iterable, optional positional arguments passed into func. kwargs : dict, optional a dictionary of keyword arguments passed into func. |
|---|---|
| Returns: | object : the return type of func. |
Notes
See more here
Examples
df = pd.DataFrame({'A': 'a b a b'.split(), 'B': [1, 2, 3, 4]}) df A B 0 a 1 1 b 2 2 a 3 3 b 4
To get the difference between each groups maximum and minimum value in one pass, you can do
df.groupby('A').pipe(lambda x: x.max() - x.min()) B A a 2 b 2