dask.dataframe.DataFrame.rename

dask.dataframe.DataFrame.rename¶

DataFrame.rename(index=None, columns=None)[source]¶

Rename columns or index labels.

This docstring was copied from pandas.core.frame.DataFrame.rename.

Some inconsistencies with the Dask version may exist.

Function / dict values must be unique (1-to-1). Labels not contained in a dict / Series will be left as-is. Extra labels listed don’t throw an error.

See the user guide for more.

Parameters

mapperdict-like or function (Not supported in Dask): Dict-like or function transformations to apply to that axis’ values. Use either mapper and axis to specify the axis to target with mapper, or index and columns.
indexdict-like or function (Not supported in Dask): Alternative to specifying axis (mapper, axis=0 is equivalent to index=mapper).
columnsdict-like or function: Alternative to specifying axis (mapper, axis=1 is equivalent to columns=mapper).
axis{0 or ‘index’, 1 or ‘columns’}, default 0 (Not supported in Dask): Axis to target with mapper. Can be either the axis name (‘index’, ‘columns’) or number (0, 1). The default is ‘index’.
copybool, default True (Not supported in Dask): Also copy underlying data.

Note

The copy keyword will change behavior in pandas 3.0. Copy-on-Write will be enabled by default, which means that all methods with a copy keyword will use a lazy copy mechanism to defer the copy and ignore the copy keyword. The copy keyword will be removed in a future version of pandas.

You can already get the future behavior and improvements through enabling copy on write pd.options.mode.copy_on_write = True
inplacebool, default False (Not supported in Dask): Whether to modify the DataFrame rather than creating a new one. If True then value of copy is ignored.
levelint or level name, default None (Not supported in Dask): In case of a MultiIndex, only rename labels in the specified level.
errors{‘ignore’, ‘raise’}, default ‘ignore’ (Not supported in Dask): If ‘raise’, raise a KeyError when a dict-like mapper, index, or columns contains labels that are not present in the Index being transformed. If ‘ignore’, existing keys will be renamed and extra keys will be ignored.

Returns

DataFrame or None: DataFrame with the renamed axis labels or None if inplace=True.

Raises

KeyError: If any of the labels is not found in the selected axis and “errors=’raise’”.

See also

DataFrame.rename_axis: Set the name of the axis.

Examples

DataFrame.rename supports two calling conventions

(index=index_mapper, columns=columns_mapper, ...)
(mapper, axis={'index', 'columns'}, ...)

We highly recommend using keyword arguments to clarify your intent.

Rename columns using a mapping:

>>> df = pd.DataFrame({"A": [1, 2, 3], "B": [4, 5, 6]})  
>>> df.rename(columns={"A": "a", "B": "c"})  
   a  c
0  1  4
1  2  5
2  3  6

Rename index using a mapping:

>>> df.rename(index={0: "x", 1: "y", 2: "z"})  
   A  B
x  1  4
y  2  5
z  3  6

Cast index labels to a different type:

>>> df.index  
RangeIndex(start=0, stop=3, step=1)
>>> df.rename(index=str).index  
Index(['0', '1', '2'], dtype='object')

>>> df.rename(columns={"A": "a", "B": "b", "C": "c"}, errors="raise")  
Traceback (most recent call last):
KeyError: ['C'] not found in axis

Using axis-style parameters:

>>> df.rename(str.lower, axis='columns')  
   a  b
0  1  4
1  2  5
2  3  6

>>> df.rename({1: 2, 2: 4}, axis='index')  
   A  B
0  1  4
2  2  5
4  3  6

dask.dataframe.DataFrame.reduction

dask.dataframe.DataFrame.repartition