Parse the use of whiletrue in Python

Source: Internet
Author: User
This article describes how to parse whiletrue in Python. whiletrue is used to create an infinite loop. Infinite Loop
If the condition determination statement is always true, the loop will be executed infinitely, as shown in the following example:

#! /Usr/bin/python #-*-coding: UTF-8-*-var = 1 while var = 1: # This condition is always true, the loop will be infinitely executed num = raw_input ("Enter a number:") print "You entered:", numprint "Good bye! "

Output result of the above instance:

Enter a number :20You entered: 20Enter a number :29You entered: 29Enter a number :3You entered: 3Enter a number between :Traceback (most recent call last): File "", line 5, in 
    num = raw_input("Enter a number :")KeyboardInterrupt

Note: You can use CTRL + C to interrupt the loop.

Python while 1 vs while True
Before Python 3.0, their execution was different:
While 1, python will be optimized, and the 1 condition will not be checked for each loop, so the performance will be good
While True: True is not a reserved word before 3 K in python. you can set True to 0. Therefore, you must compare the value of True at a time.

After Python 3.0, True/False are reserved words,

>>> True = 10

An error is reported.
Therefore, after python 3, while 1 and while True have the same effect and will be optimized by the interpreter.

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