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DOC: Update pandas.Series.copy docstring #20261

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102 changes: 95 additions & 7 deletions pandas/core/generic.py
Original file line number Diff line number Diff line change
Expand Up @@ -4506,22 +4506,110 @@ def astype(self, dtype, copy=True, errors='raise', **kwargs):

def copy(self, deep=True):
"""
Make a copy of this objects data.
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).
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Unless you want to have a Notes section I would say "see Examples below" as a reference to the section actually showing that


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indices are immutable, mention this

When `deep=False`, a new object will be created without copying
the calling object's data (only a reference to the data is
copied). Any changes to the data of the original will be reflected
in the shallow copy (and vice versa).

Parameters
----------
deep : boolean or string, default True
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`True` instead of just True

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str instead of string

Make a deep copy, including a copy of the data and the indices.
With ``deep=False`` neither the indices or the data are copied.

Note that when ``deep=True`` data is copied, 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.
With `deep=False` neither the indices or the data are copied.
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"neither...nor" instead of "or"


Returns
-------
copy : type of caller
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Move "type of caller" down as the description and say something like "Object type matches caller."

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Still need to clean up the line that says copy : type of caller. I would explicitly list the objects that could be a caller of this function, which I assume would make this Series or DataFrame but if there's anything else be sure to add that.

Otherwise nice job on all the edits - changes I requested all lgtm

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Yes, I would make this "Series or DataFrame"


Notes
-----
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).
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"...copies object data (see examples below)." - reduces some punctuation and saves space


Examples
--------
>>> s = pd.Series([1, 2], index=["a", "b"])
>>> s
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This is simple enough that I don't think you need to print

a 1
b 2
dtype: int64
>>> s_copy = s.copy()
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blank line between cases (if they are separate / distinct)

>>> s_copy
a 1
b 2
dtype: int64

Shallow copy versus default (deep) copy:
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Since this is a "section header" can you get it to render in bold (i.e. between asterisks)?


In a shallow copy, the data is shared with the original object.

>>> s = pd.Series([1,2], index=["a", "b"])
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Space after first comma

>>> deep_copy = s.copy()
>>> shallow_copy = s.copy(deep=False)
>>> id(s) == id(shallow_copy)
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These examples are certainly comprehensive but perhaps too verbose. Can you refactor to make the index / values comparisons fit on one line? Similar comment with the value assignment - any consolidation will make it more readable

False
>>> id(s.values) == id(shallow_copy.values)
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Just again wondering if these can be more concise. Perhaps choosing a different variable name will allow you to do id(s.values) == id(shlw.values) and id(s.index) == id(shlw.values)

True
>>> id(s) == id(deep_copy)
False
>>> id(s.values) == id(deep_copy.values)
False
>>> s[0] = 3
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break this up with some text describing what you are showing

>>> s
a 3
b 2
dtype: int64
>>> shallow_copy
a 3
b 2
dtype: int64
>>> deep_copy
a 1
b 2
dtype: int64
>>> shallow_copy[0] = 4
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Instead of having two different assignments I think you can have s[0] = 3 and then this line both before printing any of the objects. Gets you the same result and covers the same concepts in less lines

>>> s
a 4
b 2
dtype: int64
>>> shallow_copy
a 4
b 2
dtype: int64
>>> deep_copy
a 1
b 2
dtype: int64

When copying an object containing python objects, deep copy will
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Capitalize Python and maybe say "a deep copy"

copy the data, but will not do so recursively.

>>> s = pd.Series([[1, 2], [3, 4]])
>>> s_copy = s.copy()
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show this with a deep copy

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I wasn't sure how to address this comment - do you mean to show the behavior of
.copy(deep=True) versus the std python copy.deepcopy()? I was trying to show an example of how a (deep=True) copy isn't necessarily a deep copy in the standard python sense, but maybe I should remove this example entirely since it's already mentioned as a caveat in the Notes section?

>>> s[0][0] = 10
>>> s
0 [10, 2]
1 [3, 4]
dtype: object
>>> s_copy
0 [10, 2]
1 [3, 4]
dtype: object

For deep-copying python objects, the following can be used:
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this last example is not necessary


>>> import copy
>>> deep_deep_copy = pd.Series(copy.deepcopy(s.values),
... index=copy.deepcopy(s.index))
"""
data = self._data.copy(deep=deep)
return self._constructor(data).__finalize__(self)
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