Deep Copy and Shallow Copy

Deep Copy and Shallow Copy

Date : 04/10/2019

copy module is used to create for shallow and deep copy operations Python.

Shallow copy=>create a new object and store the reference of original elements.

import copy
var1=[1,2,3,4]
var2=copy.copy(var1)
var1
[1, 2, 3, 4]
var2
[1, 2, 3, 4]

Example for Shallow copy using nested list:

var1=[[1,2],2,3]
var2=copy.copy(var1)
var1
[[1, 2], 2, 3]
var2
[[1, 2], 2, 3]
var2.append(30)
var2
[[1, 2], 2, 3, 30]
var1
[[1, 2], 2, 3]
var2[0][0]=90
var2
[[90, 2], 2, 3, 30]
var1
[[90, 2], 2, 3]

Deepcopy=>create the new object and add the nested objects and save the original elements.

Example for deep copy:

import copy
var1=[1,2,3,4]
var2=copy.deepcopy(var1)
var1
[1, 2, 3, 4]
var2
[1, 2, 3, 4]
var2.append(90)
var1
[1, 2, 3, 4]
var2
[1, 2, 3, 4, 90]

Example for deep copy using nested list:

import copy
var1=[[1,2],[2,3],[3,4]]
var2=copy.deepcopy(var1)
var1
[[1, 2], [2, 3], [3, 4]]
var2
[[1, 2], [2, 3], [3, 4]]
var2[0][0]=90
var2
[[90, 2], [2, 3], [3, 4]]
var1
[[1, 2], [2, 3], [3, 4]]

Thanks for using Pheonix solutions.