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Pandas DataFrame apply() Method

❮ DataFrame Reference


Return the sum of each row by applying a function:

import pandas as pd

def calc_sum(x):
return x.sum()

data = {
  "x": [50, 40, 30],
  "y": [300, 1112, 42]

df = pd.DataFrame(data)

x = df.apply(calc_sum)

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Definition and Usage

The apply() method allows you to apply a function along one of the axis of the DataFrame, default 0, which is the index (row) axis.


dataframe.apply(func, axis, raw, result_type, args, kwds)


The axis, raw, result_type, and args parameters are keyword arguments.

Parameter Value Description
func   Required. A function to apply to the DataFrame.
axis 0
Optional, Which axis to apply the function to. default 0.
raw True
Optional, default False. Set to true if the row/column should be passed as an ndarray object
result_type 'expand'
Optional, default None. Specifies how the result will be returned
args a tuple Optional, arguments to send into the function
kwds keyword arguments Optional, keyword arguments to send into the function

Return Value

A DataFrame or a Series object, with the changes.

This function does NOT make changes to the original DataFrame object.

❮ DataFrame Reference