Python List copy()

February 2, 2021

copy() in Python List

The copy() method returns the copy of the list in python.

When we use the “=” sign to copy the list, if we modify the copied list then changes are also reflected back in the original list. So here we have to create a shallow copy of the list such that when we modify something in the copied list, changes are not reflected back in the original list.

Syntax :

copyList = myList.copy()

Return Type :

The copy() method returns a shallow copy of the list in python.

Using the copy() method

#copy() in python list

myList = [ 1, 2, 9, 4, 4, 2 ]

#all the values of myList is copied to the copyList
copyList = myList.copy()

print(“Before Adding Element”)
print(myList)
print(copyList)

#modifying copied list
copyList.append(10)

#changes is reflected in only copyList not in myList
print(“After adding new element in copyList”)
print(myList)
print(copyList)

Output :

Before Adding Element
[1, 2, 9, 4, 4, 2]
[1, 2, 9, 4, 4, 2]

After adding new element in copyList
[1, 2, 9, 4, 4, 2]
[1, 2, 9, 4, 4, 2, 10]

Using ” = ” Operator

# “=” in python list

myList = [ 1, 2, 9, 4, 4, 2 ]

#all the values of myList is assigned to the copyList
copyList = myList

print(“Before Adding Element”)
print(myList)
print(copyList)

#modifying copied List
copyList.append(10)

#changes is reflected in only copyList not in myList
print(“After adding new element in copyList”)
print(myList)
print(copyList)

Output :

Before Adding Element
[1, 2, 9, 4, 4, 2]
[1, 2, 9, 4, 4, 2]

After adding new element in copyList
[1, 2, 9, 4, 4, 2, 10]
[1, 2, 9, 4, 4, 2, 10]

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