Python Pandas - Subset DataFrame by Column Name

To create a subset of DataFrame by column name, use the square brackets. Use the DataFrame with square brackets (indexing operator) and the specific column name like this ?

dataFrame['column_name']

Syntax

# Single column - returns a Series
dataFrame['column_name']

# Multiple columns - returns a DataFrame
dataFrame[['col1', 'col2']]

Example - Single Column Subset

Let us create a DataFrame and extract a single column ?

import pandas as pd

# Create a Pandas DataFrame with Product records
dataFrame = pd.DataFrame({
    "Product": ["SmartTV", "ChromeCast", "Speaker", "Earphone"],
    "Opening_Stock": [300, 700, 1200, 1500], 
    "Closing_Stock": [200, 500, 1000, 900]
})

print("DataFrame...")
print(dataFrame)

print("\nDisplaying a subset (Product column):")
print(dataFrame['Product'])

DataFrame...
   Closing_Stock  Opening_Stock    Product
0            200            300    SmartTV
1            500            700  ChromeCast
2           1000           1200    Speaker
3            900           1500   Earphone

Displaying a subset (Product column):
0      SmartTV
1    ChromeCast
2      Speaker
3     Earphone
Name: Product, dtype: object

Example - Multiple Column Subset

To select multiple columns, pass a list of column names ?

import pandas as pd

dataFrame = pd.DataFrame({
    "Product": ["SmartTV", "ChromeCast", "Speaker", "Earphone"],
    "Opening_Stock": [300, 700, 1200, 1500], 
    "Closing_Stock": [200, 500, 1000, 900]
})

print("Original DataFrame:")
print(dataFrame)

print("\nSubset with multiple columns:")
print(dataFrame[['Product', 'Closing_Stock']])

Original DataFrame:
   Closing_Stock  Opening_Stock    Product
0            200            300    SmartTV
1            500            700  ChromeCast
2           1000           1200    Speaker
3            900           1500   Earphone

Subset with multiple columns:
    Product  Closing_Stock
0   SmartTV            200
1  ChromeCast            500
2   Speaker           1000
3  Earphone            900

Key Points

Conclusion

Use square brackets with a column name to subset DataFrames. Single columns return a Series, while multiple columns return a DataFrame. This is the most common way to select specific columns in pandas.