Pandas DataFrame.isin

Pandas DataFrame.isin

The DataFrame.isin method in pandas is used to check whether each element in a DataFrame is contained in a specified set of values. It returns a DataFrame of the same shape with boolean values indicating the presence of each element in the provided set.

Syntax

The syntax for DataFrame.isin is:

DataFrame.isin(values)

Here, DataFrame refers to the pandas DataFrame being checked.

Parameters

Returns

A DataFrame of boolean values of the same shape as the input DataFrame, indicating whether each element is in values.

Examples

Checking Membership in a List

Use isin to check if elements in a DataFrame are present in a list of values.

Python Program

import pandas as pd

# Create a DataFrame
data = {
    'Name': ['Arjun', 'Ram', 'Priya'],
    'Age': [25, 30, 35],
    'City': ['Delhi', 'Mumbai', 'Chennai']
}
df = pd.DataFrame(data)

# Check if elements are in the provided list
values_to_check = ['Arjun', 'Mumbai', 30]
print("Boolean DataFrame indicating membership in the list:")
print(df.isin(values_to_check))

Output

Boolean DataFrame indicating membership in the list:
    Name    Age   City
0   True  False  False
1  False   True   True
2  False  False  False

Checking Membership Using a Dictionary

Use a dictionary to specify values for specific columns to check for membership.

Python Program

import pandas as pd

# Create a DataFrame
data = {
    'Name': ['Arjun', 'Ram', 'Priya'],
    'Age': [25, 30, 35],
    'City': ['Delhi', 'Mumbai', 'Chennai']
}
df = pd.DataFrame(data)

# Check membership using a dictionary
values_to_check = {
    'Name': ['Arjun', 'Priya'],
    'City': ['Delhi']
}
print("Boolean DataFrame indicating membership using a dictionary:")
print(df.isin(values_to_check))

Output

Boolean DataFrame indicating membership using a dictionary:
    Name    Age   City
0   True  False   True
1  False  False  False
2   True  False  False

Checking Membership Using a Set

You can also use a set to check for membership in a DataFrame.

Python Program

import pandas as pd

# Create a DataFrame
data = {
    'Name': ['Arjun', 'Ram', 'Priya'],
    'Age': [25, 30, 35],
    'City': ['Delhi', 'Mumbai', 'Chennai']
}
df = pd.DataFrame(data)

# Check membership using a set
values_to_check = {'Arjun', 'Chennai', 25}
print("Boolean DataFrame indicating membership using a set:")
print(df.isin(values_to_check))

Output

Boolean DataFrame indicating membership using a set:
    Name    Age   City
0   True   True  False
1  False  False  False
2  False  False   True

Using isin for Filtering Rows

The isin method is often used to filter rows based on conditions.

Python Program

import pandas as pd

# Create a DataFrame
data = {
    'Name': ['Arjun', 'Ram', 'Priya'],
    'Age': [25, 30, 35],
    'City': ['Delhi', 'Mumbai', 'Chennai']
}
df = pd.DataFrame(data)

# Filter rows where 'City' is in the given list
filtered_df = df[df['City'].isin(['Delhi', 'Chennai'])]
print("Filtered DataFrame:")
print(filtered_df)

Output

Filtered DataFrame:
    Name  Age    City
0  Arjun   25   Delhi
2  Priya   35  Chennai

Summary

In this tutorial, we explored the DataFrame.isin method in pandas. Key takeaways include:

• Using isin to check element membership in a list, set, or dictionary.
• Returning a boolean DataFrame indicating membership.
• Using isin for filtering rows based on conditions.

The DataFrame.isin method is a versatile tool for checking membership in pandas DataFrames.