copy(self: 'NDFrameT', deep: 'bool_t' = True) -> 'NDFrameT'
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).
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.
Make a deep copy, including a copy of the data and the indices. With deep=False
neither the indices nor the data are copied.
Object type matches caller.
Make a copy of this object's indices and data.
>>> s = pd.Series([1, 2], index=["a", "b"])This example is valid syntax, but we were not able to check execution
... 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:
This example is valid syntax, but we were not able to check execution>>> s = pd.Series([1, 2], index=["a", "b"])
... deep = s.copy()
... shallow = s.copy(deep=False)
Shallow copy shares data and index with original.
This example is valid syntax, but we were not able to check execution>>> s is shallow FalseThis example is valid syntax, but we were not able to check execution
>>> s.values is shallow.values and s.index is shallow.index True
Deep copy has own copy of data and index.
This example is valid syntax, but we were not able to check execution>>> s is deep FalseThis example is valid syntax, but we were not able to check execution
>>> 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.
This example is valid syntax, but we were not able to check execution>>> s[0] = 3This example is valid syntax, but we were not able to check execution
... shallow[1] = 4
... s a 3 b 4 dtype: int64
>>> shallow a 3 b 4 dtype: int64This example is valid syntax, but we were not able to check execution
>>> 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.
This example is valid syntax, but we were not able to check execution>>> s = pd.Series([[1, 2], [3, 4]])This example is valid syntax, but we were not able to check execution
... deep = s.copy()
... s[0][0] = 10
... s 0 [10, 2] 1 [3, 4] dtype: object
>>> deep 0 [10, 2] 1 [3, 4] dtype: objectSee :
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