Mastering Pandas Series Apply Method

Introduction

The apply() method in pandas allows us to apply a function to the values of a Series. It can be used to apply either a Python method or a NumPy ufunc to the entire Series or to individual elements of the Series.

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Skills Graph

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Create a Series

First, let's create a Series using the pd.Series() function from the pandas library. We will pass a list of numbers to the function to create the Series.

import pandas as pd

s = pd.Series([1, 2, 3])

Apply a NumPy ufunc

Next, we can apply a NumPy ufunc, such as np.pi, to the values of the Series. In this example, we will multiply each value of the Series by the value of pi using a lambda function.

import numpy as np

s.apply(lambda x: x * np.pi)

Apply a Python method

We can also apply a Python method to the Series. In this example, we will use the lower() method to convert the elements of the Series to lowercase.

s.apply(lambda x: x.lower())

Apply a function with condition

Lastly, we can apply a lambda function with a condition to the Series. In this example, we will check if each value in the Series is between 2 and 5 and return True or False.

s.apply(lambda x: x >= 2 and x <= 5)

Summary

The apply() method in pandas allows us to apply a function to the values of a Series. We can use it to apply a NumPy ufunc or a Python method to the entire Series or to individual elements of the Series. It is a versatile method that can be used to perform various operations on the elements of a Series.

Pandas Series Apply Method