Module « pandas »
Signature de la fonction concat
def concat(objs: Union[Iterable[ForwardRef('NDFrame')], Mapping[Optional[Hashable], ForwardRef('NDFrame')]], axis=0, join='outer', ignore_index: bool = False, keys=None, levels=None, names=None, verify_integrity: bool = False, sort: bool = False, copy: bool = True) -> Union[ForwardRef('DataFrame'), ForwardRef('Series')]
Description
concat.__doc__
Concatenate pandas objects along a particular axis with optional set logic
along the other axes.
Can also add a layer of hierarchical indexing on the concatenation axis,
which may be useful if the labels are the same (or overlapping) on
the passed axis number.
Parameters
----------
objs : a sequence or mapping of Series or DataFrame objects
If a mapping is passed, the sorted keys will be used as the `keys`
argument, unless it is passed, in which case the values will be
selected (see below). Any None objects will be dropped silently unless
they are all None in which case a ValueError will be raised.
axis : {0/'index', 1/'columns'}, default 0
The axis to concatenate along.
join : {'inner', 'outer'}, default 'outer'
How to handle indexes on other axis (or axes).
ignore_index : bool, default False
If True, do not use the index values along the concatenation axis. The
resulting axis will be labeled 0, ..., n - 1. This is useful if you are
concatenating objects where the concatenation axis does not have
meaningful indexing information. Note the index values on the other
axes are still respected in the join.
keys : sequence, default None
If multiple levels passed, should contain tuples. Construct
hierarchical index using the passed keys as the outermost level.
levels : list of sequences, default None
Specific levels (unique values) to use for constructing a
MultiIndex. Otherwise they will be inferred from the keys.
names : list, default None
Names for the levels in the resulting hierarchical index.
verify_integrity : bool, default False
Check whether the new concatenated axis contains duplicates. This can
be very expensive relative to the actual data concatenation.
sort : bool, default False
Sort non-concatenation axis if it is not already aligned when `join`
is 'outer'.
This has no effect when ``join='inner'``, which already preserves
the order of the non-concatenation axis.
.. versionchanged:: 1.0.0
Changed to not sort by default.
copy : bool, default True
If False, do not copy data unnecessarily.
Returns
-------
object, type of objs
When concatenating all ``Series`` along the index (axis=0), a
``Series`` is returned. When ``objs`` contains at least one
``DataFrame``, a ``DataFrame`` is returned. When concatenating along
the columns (axis=1), a ``DataFrame`` is returned.
See Also
--------
Series.append : Concatenate Series.
DataFrame.append : Concatenate DataFrames.
DataFrame.join : Join DataFrames using indexes.
DataFrame.merge : Merge DataFrames by indexes or columns.
Notes
-----
The keys, levels, and names arguments are all optional.
A walkthrough of how this method fits in with other tools for combining
pandas objects can be found `here
<https://pandas.pydata.org/pandas-docs/stable/user_guide/merging.html>`__.
Examples
--------
Combine two ``Series``.
>>> s1 = pd.Series(['a', 'b'])
>>> s2 = pd.Series(['c', 'd'])
>>> pd.concat([s1, s2])
0 a
1 b
0 c
1 d
dtype: object
Clear the existing index and reset it in the result
by setting the ``ignore_index`` option to ``True``.
>>> pd.concat([s1, s2], ignore_index=True)
0 a
1 b
2 c
3 d
dtype: object
Add a hierarchical index at the outermost level of
the data with the ``keys`` option.
>>> pd.concat([s1, s2], keys=['s1', 's2'])
s1 0 a
1 b
s2 0 c
1 d
dtype: object
Label the index keys you create with the ``names`` option.
>>> pd.concat([s1, s2], keys=['s1', 's2'],
... names=['Series name', 'Row ID'])
Series name Row ID
s1 0 a
1 b
s2 0 c
1 d
dtype: object
Combine two ``DataFrame`` objects with identical columns.
>>> df1 = pd.DataFrame([['a', 1], ['b', 2]],
... columns=['letter', 'number'])
>>> df1
letter number
0 a 1
1 b 2
>>> df2 = pd.DataFrame([['c', 3], ['d', 4]],
... columns=['letter', 'number'])
>>> df2
letter number
0 c 3
1 d 4
>>> pd.concat([df1, df2])
letter number
0 a 1
1 b 2
0 c 3
1 d 4
Combine ``DataFrame`` objects with overlapping columns
and return everything. Columns outside the intersection will
be filled with ``NaN`` values.
>>> df3 = pd.DataFrame([['c', 3, 'cat'], ['d', 4, 'dog']],
... columns=['letter', 'number', 'animal'])
>>> df3
letter number animal
0 c 3 cat
1 d 4 dog
>>> pd.concat([df1, df3], sort=False)
letter number animal
0 a 1 NaN
1 b 2 NaN
0 c 3 cat
1 d 4 dog
Combine ``DataFrame`` objects with overlapping columns
and return only those that are shared by passing ``inner`` to
the ``join`` keyword argument.
>>> pd.concat([df1, df3], join="inner")
letter number
0 a 1
1 b 2
0 c 3
1 d 4
Combine ``DataFrame`` objects horizontally along the x axis by
passing in ``axis=1``.
>>> df4 = pd.DataFrame([['bird', 'polly'], ['monkey', 'george']],
... columns=['animal', 'name'])
>>> pd.concat([df1, df4], axis=1)
letter number animal name
0 a 1 bird polly
1 b 2 monkey george
Prevent the result from including duplicate index values with the
``verify_integrity`` option.
>>> df5 = pd.DataFrame([1], index=['a'])
>>> df5
0
a 1
>>> df6 = pd.DataFrame([2], index=['a'])
>>> df6
0
a 2
>>> pd.concat([df5, df6], verify_integrity=True)
Traceback (most recent call last):
...
ValueError: Indexes have overlapping values: ['a']
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