Series.copy(self, deep=True)
[source]
Make a copy of this object’s indices and data.
When deep=True
(default), a new object will be created with a copy of the calling object’s data and indices. Modifications to the data or indices of the copy will not be reflected in the original object (see notes below).
When deep=False
, a new object will be created without copying the calling object’s data or index (only references to the data and index are copied). Any changes to the data of the original will be reflected in the shallow copy (and vice versa).
Parameters: |
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Returns: |
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When deep=True
, data is copied but actual Python objects will not be copied recursively, only the reference to the object. This is in contrast to copy.deepcopy
in the Standard Library, which recursively copies object data (see examples below).
While Index
objects are copied when deep=True
, the underlying numpy array is not copied for performance reasons. Since Index
is immutable, the underlying data can be safely shared and a copy is not needed.
>>> s = pd.Series([1, 2], index=["a", "b"]) >>> s a 1 b 2 dtype: int64
>>> s_copy = s.copy() >>> s_copy a 1 b 2 dtype: int64
Shallow copy versus default (deep) copy:
>>> s = pd.Series([1, 2], index=["a", "b"]) >>> deep = s.copy() >>> shallow = s.copy(deep=False)
Shallow copy shares data and index with original.
>>> s is shallow False >>> s.values is shallow.values and s.index is shallow.index True
Deep copy has own copy of data and index.
>>> s is deep False >>> s.values is deep.values or s.index is deep.index False
Updates to the data shared by shallow copy and original is reflected in both; deep copy remains unchanged.
>>> s[0] = 3 >>> shallow[1] = 4 >>> s a 3 b 4 dtype: int64 >>> shallow a 3 b 4 dtype: int64 >>> deep a 1 b 2 dtype: int64
Note that when copying an object containing Python objects, a deep copy will copy the data, but will not do so recursively. Updating a nested data object will be reflected in the deep copy.
>>> s = pd.Series([[1, 2], [3, 4]]) >>> deep = s.copy() >>> s[0][0] = 10 >>> s 0 [10, 2] 1 [3, 4] dtype: object >>> deep 0 [10, 2] 1 [3, 4] dtype: object
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https://pandas.pydata.org/pandas-docs/version/0.25.0/reference/api/pandas.Series.copy.html