Setting & Resetting Index

The index is the row label in a DataFrame. You can customize it for better data organization and lookup.

Default Index

By default, Pandas uses integer index starting from 0:

Setting a Column as Index

Use set_index() to make a column the index:

Resetting the Index

Use reset_index() to move the index back to a column:

Multi-Level Index

Create hierarchical indexes:

Modifying Index in Place

Use inplace=True to modify the original DataFrame:

Renaming the Index

Give your index a name:

Exercise: Set Index

Exercise: Reset Index

Key Points

• set_index('column') makes a column the index
• reset_index() moves index back to a column
• reset_index(drop=True) discards the index
• inplace=True modifies the original DataFrame
• Multi-level indexes use tuples for lookup
• Index enables fast .loc[] lookups