Classe « DataFrame »

Méthode pandas.DataFrame.pivot

Signature de la méthode pivot

def pivot(self, index=None, columns=None, values=None) -> 'DataFrame' 

Description

pivot.__doc__

Return reshaped DataFrame organized by given index / column values.

Reshape data (produce a "pivot" table) based on column values. Uses
unique values from specified `index` / `columns` to form axes of the
resulting DataFrame. This function does not support data
aggregation, multiple values will result in a MultiIndex in the
columns. See the :ref:`User Guide <reshaping>` for more on reshaping.

Parameters
----------
index : str or object or a list of str, optional
    Column to use to make new frame's index. If None, uses
    existing index.

    .. versionchanged:: 1.1.0
       Also accept list of index names.

columns : str or object or a list of str
    Column to use to make new frame's columns.

    .. versionchanged:: 1.1.0
       Also accept list of columns names.

values : str, object or a list of the previous, optional
    Column(s) to use for populating new frame's values. If not
    specified, all remaining columns will be used and the result will
    have hierarchically indexed columns.

Returns
-------
DataFrame
    Returns reshaped DataFrame.

Raises
------
ValueError:
    When there are any `index`, `columns` combinations with multiple
    values. `DataFrame.pivot_table` when you need to aggregate.

See Also
--------
DataFrame.pivot_table : Generalization of pivot that can handle
    duplicate values for one index/column pair.
DataFrame.unstack : Pivot based on the index values instead of a
    column.
wide_to_long : Wide panel to long format. Less flexible but more
    user-friendly than melt.

Notes
-----
For finer-tuned control, see hierarchical indexing documentation along
with the related stack/unstack methods.

Examples
--------
>>> df = pd.DataFrame({'foo': ['one', 'one', 'one', 'two', 'two',
...                            'two'],
...                    'bar': ['A', 'B', 'C', 'A', 'B', 'C'],
...                    'baz': [1, 2, 3, 4, 5, 6],
...                    'zoo': ['x', 'y', 'z', 'q', 'w', 't']})
>>> df
    foo   bar  baz  zoo
0   one   A    1    x
1   one   B    2    y
2   one   C    3    z
3   two   A    4    q
4   two   B    5    w
5   two   C    6    t

>>> df.pivot(index='foo', columns='bar', values='baz')
bar  A   B   C
foo
one  1   2   3
two  4   5   6

>>> df.pivot(index='foo', columns='bar')['baz']
bar  A   B   C
foo
one  1   2   3
two  4   5   6

>>> df.pivot(index='foo', columns='bar', values=['baz', 'zoo'])
      baz       zoo
bar   A  B  C   A  B  C
foo
one   1  2  3   x  y  z
two   4  5  6   q  w  t

You could also assign a list of column names or a list of index names.

>>> df = pd.DataFrame({
...        "lev1": [1, 1, 1, 2, 2, 2],
...        "lev2": [1, 1, 2, 1, 1, 2],
...        "lev3": [1, 2, 1, 2, 1, 2],
...        "lev4": [1, 2, 3, 4, 5, 6],
...        "values": [0, 1, 2, 3, 4, 5]})
>>> df
    lev1 lev2 lev3 lev4 values
0   1    1    1    1    0
1   1    1    2    2    1
2   1    2    1    3    2
3   2    1    2    4    3
4   2    1    1    5    4
5   2    2    2    6    5

>>> df.pivot(index="lev1", columns=["lev2", "lev3"],values="values")
lev2    1         2
lev3    1    2    1    2
lev1
1     0.0  1.0  2.0  NaN
2     4.0  3.0  NaN  5.0

>>> df.pivot(index=["lev1", "lev2"], columns=["lev3"],values="values")
      lev3    1    2
lev1  lev2
   1     1  0.0  1.0
         2  2.0  NaN
   2     1  4.0  3.0
         2  NaN  5.0

A ValueError is raised if there are any duplicates.

>>> df = pd.DataFrame({"foo": ['one', 'one', 'two', 'two'],
...                    "bar": ['A', 'A', 'B', 'C'],
...                    "baz": [1, 2, 3, 4]})
>>> df
   foo bar  baz
0  one   A    1
1  one   A    2
2  two   B    3
3  two   C    4

Notice that the first two rows are the same for our `index`
and `columns` arguments.

>>> df.pivot(index='foo', columns='bar', values='baz')
Traceback (most recent call last):
   ...
ValueError: Index contains duplicate entries, cannot reshape