Set the DataFrame index using existing columns.

Set the DataFrame index (row labels) using one or more existing columns or arrays (of the correct length). The index can replace the existing index or expand on it.

This parameter can be either a single column key, a single array of the same length as the calling DataFrame, or a list containing an arbitrary combination of column keys and arrays. Here, “array” encompasses Series, Index, np.ndarray, and instances of Iterator.

Delete columns to be used as the new index.

Whether to append columns to existing index.

Whether to modify the DataFrame rather than creating a new one.

Check the new index for duplicates. Otherwise defer the check until necessary. Setting to False will improve the performance of this method.

Changed row labels or None if inplace=True.

See also

Opposite of set_index.

Change to new indices or expand indices.

Change to same indices as other DataFrame.

Examples

Set the index to become the ‘month’ column:

Create a MultiIndex using columns ‘year’ and ‘month’:

Create a MultiIndex using an Index and a column:

Create a MultiIndex using two Series: