Pandas DataFrame.get

Pandas DataFrame.get

The DataFrame.get method in pandas is used to retrieve a column or columns from a DataFrame by key (column name). If the key is not found, it returns a default value instead of raising an error. This method is useful for safely accessing columns in a DataFrame.

Syntax

The syntax for DataFrame.get is:

DataFrame.get(key, default=None)

Here, DataFrame refers to the pandas DataFrame from which the column is retrieved.

Parameters

Returns

A Series or DataFrame corresponding to the specified key, or the default value if the key is not found.

Examples

Retrieving a Column by Key

Use get to retrieve a column from a DataFrame.

Python Program

import pandas as pd

# Create a DataFrame
data = {
    'Name': ['Arjun', 'Ram', 'Priya'],
    'Age': [25, 30, 35],
    'Salary': [70000.5, 80000.0, 90000.0]
}
df = pd.DataFrame(data)

# Retrieve the 'Age' column
print("Age Column:")
age_column = df.get('Age')
print(age_column)

Output

Age Column:
0    25
1    30
2    35
Name: Age, dtype: int64

Handling Missing Keys with Default Values

Provide a default value to return when the specified key is not found.

Python Program

import pandas as pd

# Create a DataFrame
data = {
    'Name': ['Arjun', 'Ram', 'Priya'],
    'Age': [25, 30, 35],
    'Salary': [70000.5, 80000.0, 90000.0]
}
df = pd.DataFrame(data)

# Attempt to retrieve a non-existent column with a default value
print("Non-Existent Column:")
default_column = df.get('Department', default='Not Available')
print(default_column)

Output

Non-Existent Column:
Not Available

Retrieving Multiple Columns

Use a list of keys to retrieve multiple columns from a DataFrame.

Python Program

import pandas as pd

# Create a DataFrame
data = {
    'Name': ['Arjun', 'Ram', 'Priya'],
    'Age': [25, 30, 35],
    'Salary': [70000.5, 80000.0, 90000.0]
}
df = pd.DataFrame(data)

# Retrieve multiple columns
print("Selected Columns:")
selected_columns = df.get(['Name', 'Salary'])
print(selected_columns)

Output

Selected Columns:
    Name   Salary
0  Arjun  70000.5
1    Ram  80000.0
2   Priya  90000.0

Using get with an Empty DataFrame

When using get on an empty DataFrame, it will return the default value.

Python Program

import pandas as pd

# Create an empty DataFrame
df_empty = pd.DataFrame()

# Attempt to retrieve a column with a default value
print("Retrieving from an Empty DataFrame:")
default_empty = df_empty.get('Age', default='No Data')
print(default_empty)

Output

Retrieving from an Empty DataFrame:
No Data

Summary

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

• Using get to retrieve columns safely by key.
• Providing default values to handle missing keys without raising errors.
• Retrieving multiple columns or handling empty DataFrames effectively.

The DataFrame.get method is a flexible and safe way to access data in pandas DataFrames.