Shallow copy & Deep copy in Python (10)

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*Memo:

• My post explains the shallow and deep copy of a list.
• My post explains the shallow and deep copy of a tuple.
• My post explains the shallow and deep copy of the set with a frozenset.
• My post explains the shallow and deep copy of the set with a tuple.
• My post explains the shallow and deep copy of the set with an iterator.
• My post explains the shallow and deep copy of a frozenset.
• My post explains the shallow and deep copy of a dictionary.
• My post explains the shallow and deep copy of an iterator.
• My post explains the shallow and deep copy of an string.
• My post explains the shallow and deep copy of a bytearray.
• My post explains a bytes.

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The same bytes is referred to even if copied.

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A 2D bytes is experimented, doing assignment and shallow and deep copy as shown below:

*Memo:

• For a 2D bytes, both shallow and deep copy are impossible.
• A bytes has 2 demesions(D).

<Assignment>:

*Memo:

• v1 and v2 refer to the same shallow and deep bytes.
• is keyword can check if v1 and v2 refer to the same bytes.

A 2D bytes is assigned to a variable without copied as shown below:

#  Shallow bytes
#    ↓↓↓↓↓↓↓↓ 
v1 = b'abcde'
     # ↑↑↑↑↑ Deep bytes(Each byte)
v2 = v1

print(v1, v1[2]) # b'abcde' 99
print(v2, v2[2]) # b'abcde' 99

print(v1 is v2, v1[2] is v2[2])
# True True

<Shallow copy>:

*Memo:

• v1 and v2 refer to the same shallow and deep bytes.

copy.copy() doesn't shallow-copy a 2D bytes as shown below:

import copy

v1 = b'abcde'
v2 = copy.copy(v1)

print(v1, v1[2]) # abcde c
print(v2, v2[2]) # abcde c

print(v1 is v2, v1[2] is v2[2])
# True True

Slicing doesn't shallow-copy the 2D bytes as shown below:

v1 = b'abcde'
v2 = v1[:]

print(v1, v1[2]) # b'abcde' 99
print(v2, v2[2]) # b'abcde' 99

print(v1 is v2, v1[2] is v2[2])
# True True

str() doesn't shallow-copy a 2D bytes as shown below:

v1 = b'abcde'
v2 = bytes(v1)

print(v1, v1[2]) # b'abcde' 99
print(v2, v2[2]) # b'abcde' 99

print(v1 is v2, v1[2] is v2[2])
# True True

<Deep copy>:

*Memo:

• v1 and v2 refer to the same shallow and deep bytes.

copy.deepcopy() doesn't deep-copy a 2D bytes as shown below:

import copy

v1 = b'abcde'
v2 = copy.deepcopy(v1)

print(v1, v1[2]) # b'abcde' 99
print(v2, v2[2]) # b'abcde' 99

print(v1 is v2, v1[2] is v2[2])
# True True