*Memos:
- 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 an iterator.
- 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 variable assignment.
<A set with a tuple>
A set can have a tuple and iterator but cannot have a set, list and dictionary. *The same tuple is always referred to because a tuple cannot be copied according to the experiments so for the set with a tuple, only shallow copy is possible.
Normal Copy:
*Memos:
-
AandBrefer to the same shallow set and deep tuple. -
iskeyword can check ifv1andv2refer to the same set or tuple.
# Shallow set
# ↓ ↓
A = {('a',)}
# ↑↑↑↑↑↑ Deep tuple
B = A
print(A) # {('a',)}
print(B) # {('a',)}
print(A is B) # True
print(A.pop()) # ('a',)
print(B.pop()) # KeyError: 'pop from an empty set'
Shallow Copy:
copy() can do shallow copy as shown below:
*Memos:
-
AandBrefer to different shallow sets. -
AandBrefer to the same deep tuple.
A = {('a',)}
B = A.copy() # Here
print(A) # {('a',)}
print(B) # {('a',)}
print(A is B) # False
v1 = A.pop()
v2 = B.pop()
print(v1) # ('a',)
print(v2) # ('a',)
print(v1 is v2) # True
The below with copy() which can do shallow copy is equivalent to the above:
from copy import copy
A = {('a',)}
B = copy(A) # Here
print(A) # {('a',)}
print(B) # {('a',)}
print(A is B) # False
v1 = A.pop()
v2 = B.pop()
print(v1) # ('a',)
print(v2) # ('a',)
print(v1 is v2) # True
The below with deepcopy() which can do deep copy is equivalent to the above. *deepcopy() should be used because it's safe, doing copy deeply:
from copy import deepcopy
A = {('a',)}
B = deepcopy(A) # Here
print(A) # {('a',)}
print(B) # {('a',)}
print(A is B) # False
v1 = A.pop()
v2 = B.pop()
print(v1) # ('a',)
print(v2) # ('a',)
print(v1 is v2) # True
The below with set() which can do shallow copy is equivalent to the above:
A = {('a',)}
B = set(A) # Here
print(A) # {('a',)}
print(B) # {('a',)}
print(A is B) # False
v1 = A.pop()
v2 = B.pop()
print(v1) # ('a',)
print(v2) # ('a',)
print(v1 is v2) # True
Additionally, the below is the 3D set with a 2D tuple:
from copy import deepcopy
A = {(('a',),)}
B = deepcopy(A) # Here
print(A) # {(('a',),)}
print(B) # {(('a',),)}
print(A is B) # False
v1 = A.pop()
v2 = B.pop()
print(v1) # (('a',),)
print(v2) # (('a',),)
print(v1[0]) # ('a',)
print(v2[0]) # ('a',)
print(v1 is v2, v1[0] is v2[0]) # True True
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