How to Transpose DataFrame in pandas: Simple Guide

To transpose a DataFrame in pandas, use the .T attribute or the transpose() method. Both flip rows and columns, turning rows into columns and columns into rows.

Syntax

You can transpose a pandas DataFrame using either the .T attribute or the transpose() method.

• DataFrame.T: A quick attribute to transpose the DataFrame.
• DataFrame.transpose(): A method that does the same and allows optional parameters.

python

transposed_df = df.T
# or
transposed_df = df.transpose()

Example

This example shows how to create a simple DataFrame and transpose it using both .T and transpose(). The output shows rows and columns swapped.

python

import pandas as pd

# Create a sample DataFrame
df = pd.DataFrame({
    'Name': ['Alice', 'Bob'],
    'Age': [25, 30],
    'City': ['NY', 'LA']
})

# Transpose using .T
transposed1 = df.T

# Transpose using transpose()
transposed2 = df.transpose()

print('Original DataFrame:')
print(df)
print('\nTransposed with .T:')
print(transposed1)
print('\nTransposed with transpose():')
print(transposed2)

Output

Original DataFrame:
    Name  Age City
0  Alice   25   NY
1    Bob   30   LA

Transposed with .T:
           0    1
Name   Alice  Bob
Age       25   30
City      NY   LA

Transposed with transpose():
           0    1
Name   Alice  Bob
Age       25   30
City      NY   LA

Common Pitfalls

One common mistake is expecting the transpose to change the original DataFrame. It returns a new DataFrame and does not modify the original unless reassigned.

Also, transposing DataFrames with mixed data types can lead to unexpected data type changes because pandas tries to align data types in columns.

python

import pandas as pd

df = pd.DataFrame({
    'A': [1, 2],
    'B': ['x', 'y']
})

# Wrong: expecting original df to change
_ = df.T
print(df)  # df is unchanged

# Right: reassign to keep transposed
df = df.T
print(df)

Output

   A  B
0  1  x
1  2  y
     0  1
A    1  2
B    x  y

Quick Reference

Use .T for quick transpose without parameters.
Use transpose() if you want to specify axes (rarely needed).

Method	Description	Example
.T	Transpose DataFrame quickly	df.T
transpose()	Transpose with optional axes	df.transpose()

Key Takeaways

Use df.T or df.transpose() to transpose a pandas DataFrame.

Transposing swaps rows and columns but does not change the original DataFrame unless reassigned.

Mixed data types in DataFrame columns may affect the result after transpose.

Use .T for simple transpose and transpose() for more control if needed.