Python Set copy()

The copy() method returns a shallow copy of the set.

A set can be copied using = operator in Python. For example:

numbers = {1, 2, 3, 4}
new_numbers = numbers

The problem with copying the set in this way is that if you modify the numbers set, the new_numbers set is also modified.

numbers = {1, 2, 3, 4}
new_numbers = numbers

new_numbers.add(5)

print('numbers: ', numbers)
print('new_numbers: ', new_numbers)

Output

numbers:  {1, 2, 3, 4, 5}
new_numbers:  {1, 2, 3, 4, 5}

However, if you need the original set to be unchanged when the new set is modified, you can use the copy() method.

The syntax of copy() is:

set.copy()

1. copy() Parameters

It doesn’t take any parameters.

2. Return Value from copy()

The copy() method returns a shallow copy of the set.

3. Example 1: How the copy() method works for sets?

numbers = {1, 2, 3, 4}
new_numbers = numbers.copy()

new_numbers.add(5)

print('numbers: ', numbers)
print('new_numbers: ', new_numbers)

Output

numbers:  {1, 2, 3, 4}
new_numbers:  {1, 2, 3, 4, 5}