Pandas — Concatenation

Basic concat

import pandas as pd

df1 = pd.DataFrame({'A': [1, 2], 'B': [3, 4]})
df2 = pd.DataFrame({'A': [5, 6], 'B': [7, 8]})

# Vertical (rows)
result = pd.concat([df1, df2])

# Horizontal (columns)
result = pd.concat([df1, df2], axis=1)

With keys

result = pd.concat([df1, df2], keys=['df1', 'df2'])

Ignore index

result = pd.concat([df1, df2], ignore_index=True)

Handle mismatched columns

df3 = pd.DataFrame({'A': [1, 2], 'C': [5, 6]})
result = pd.concat([df1, df3], join='inner')

Mini Practice

1. Concat vertically
2. Concat horizontally
3. Add keys
4. Handle mismatched columns

Up Next

Continue with Reshape - Reshaping data.