Python Dictionary (Dictionary) copy () method

Python Dictionary (Dictionary) copy () method description

The Python dictionary (Dictionary) copy () function returns a shallow copy of a dictionary.

Grammar

Copy () method syntax:

Dict.  Copy()  

Parameters

• NA.

return value

Returns a shallow copy of a dictionary.

Instance

The following example shows how the copy () function is used:

Instance#!/usr/bin/python Dict1= {‘Name‘ ' zara age7}; dict2 = dict1 copy ( Span class= "hl-reserved" >print "New Dictinary:%s "% str (dict2

The result of the above example output is:

Newdictinary:{' age ':7,' Name ':' Zara '}   

The difference between direct assignment and copy

This can be illustrated by the following examples:

Instance#!/usr/bin/python #-*-Coding:utf-8-*- Dict1= {‘User‘:‘Runoob‘,‘Num‘:[1,2,3]}Dict2=Dict1 # Shallow copy: Reference object Dict3=Dict1.Copy() # Shallow copy: Deep copy Parent object (First level directory), sub-object (level two directory) not copy, or reference # Modify Data Dict1[‘User‘]=‘Root‘ dict1[ ' Num ]. Remove (1 Span class= "hl-comment" ># output print ( dict1) Print (dict2) print ( Dict3

The dict2 in the instance is actually a reference (alias) of the Dict1, so the output is consistent, dict3 the parent object is deeply copied, does not change with the Dict1 modification, the sub-object is a shallow copy, so modify with the Dict1.

{' Num ': [2, 3], ' User ':  ' root ' }{ ' Num ' : [2  3],  ' user ' :  ' root ' } { "num ' : [2 , 3], :  ' Runoob ' }      

Python Dictionary (Dictionary) copy () method