pandas.DataFrame.swaplevel — pandas 2.2.3 documentation (original) (raw)

DataFrame.swaplevel(i=-2, j=-1, axis=0)[source]#

Swap levels i and j in a MultiIndex.

Default is to swap the two innermost levels of the index.

Parameters:

i, jint or str

Levels of the indices to be swapped. Can pass level name as string.

axis{0 or ‘index’, 1 or ‘columns’}, default 0

The axis to swap levels on. 0 or ‘index’ for row-wise, 1 or ‘columns’ for column-wise.

Returns:

DataFrame

DataFrame with levels swapped in MultiIndex.

Examples

df = pd.DataFrame( ... {"Grade": ["A", "B", "A", "C"]}, ... index=[ ... ["Final exam", "Final exam", "Coursework", "Coursework"], ... ["History", "Geography", "History", "Geography"], ... ["January", "February", "March", "April"], ... ], ... ) df Grade Final exam History January A Geography February B Coursework History March A Geography April C

In the following example, we will swap the levels of the indices. Here, we will swap the levels column-wise, but levels can be swapped row-wise in a similar manner. Note that column-wise is the default behaviour. By not supplying any arguments for i and j, we swap the last and second to last indices.

df.swaplevel() Grade Final exam January History A February Geography B Coursework March History A April Geography C

By supplying one argument, we can choose which index to swap the last index with. We can for example swap the first index with the last one as follows.

df.swaplevel(0) Grade January History Final exam A February Geography Final exam B March History Coursework A April Geography Coursework C

We can also define explicitly which indices we want to swap by supplying values for both i and j. Here, we for example swap the first and second indices.

df.swaplevel(0, 1) Grade History Final exam January A Geography Final exam February B History Coursework March A Geography Coursework April C