Python_ Loop expression

One, while loop

As long as the conditions are met, you can always perform the action. This cycle is called the Dead loop, once triggered, as long as the conditions meet, on the wireless loop.

This condition is actually a Boolean value of-->true, False. If you want to make a decision to end the loop irregularly, you can set the variable to a Boolean value (True), and when you want to end it, reset the Boolean value (False) to end the loop.

Circulation in the daily use, but also need to cooperate with several expression methods, respectively: Break, continue, end, else, in the following article will be explained in detail.

While loop structure:

 while Condition:    action    

Printing is printed as long as NUM is less than or equal to 10:

num = 1 while num <=:    print(num    )= num + 1

Print even numbers only:

num = 1 while num <=:    if num% 2 = = 0:                #  $ operation for fetch remainder        print  (num)    = num + 1

Print only odd numbers:

num = 1 while num <=:    print(num    )= num + 2

Use of break:

Terminates the loop and terminates immediately when the loop encounters a break.

Prints an integer from 1 to 10, terminating the loop when num==4.

num = 1 while num <=:    print(num)    = num + 1    if num ==4:          Break

Usage of continue:

Jump out of the secondary loop, and then the loop continues without being affected.

This loop first is added once 1 and then to determine the printing, so the first time to print out is ' 2 ', when ' num=4 ', continue skip or end the cycle, do not perform continue results, so do not print ' 4 ', when the last cycle of ' num = 10 ', And the first time, is the first add 1, and then to determine the printing, so there will be ' 11 '.

num = 1 while num <=:    = num + 1    if num = = 4:        Continu E    print(num)

Python_ Loop expression