set copy() in python

The copy() method returns a shallow copy of the set in python. If we use "=" to copy a set to another set, when we modify in the copied set, the changes are also reflected in the original set. So we have to create a shallow copy of the set such that when we modify something in the copied set, changes are not reflected back in the original set. Syntax:

set_name.copy()

set_name: Name of the set whose copy
          we want to generate.

Parameters:The copy() method for sets doesn't take any parameters. Return value:The function returns a shallow copy of the original set. Below is the implementation of the above function: 

# Python3 program to demonstrate the use
# of join() function 

set1 = {1, 2, 3, 4} 

# function to copy the set
set2 = set1.copy() 

# prints the copied set
print(set2)       

Output:

{1, 2, 3, 4} 

Time complexity : O(1),

space complexity: O(n)

Shallow Copy Example : 

# Python program to demonstrate that copy 
# created using set copy is shallow
first = {'g', 'e', 'e', 'k', 's'}
second = first.copy()

# before adding
print 'before adding: '
print 'first: ',first
print 'second: ', second 

# Adding element to second, first does not
# change.
second.add('f')

# after adding
print 'after adding: '
print 'first: ', first
print 'second: ', second 

Output:

before adding: 
first:  set(['s', 'e', 'k', 'g'])
second:  set(['s', 'e', 'k', 'g'])
after adding: 
first:  set(['s', 'e', 'k', 'g'])
second:  set(['s', 'e', 'k', 'g', 'f'])

Time complexity : O(1)

space complexity: O(n)