python流程控制

流程控制if

why:選擇,或者比大小

what:流程控制語句if

how:

    1,基本語句:

  if   條件:
       代碼塊

    2,五種情況:

        a,單獨if

      if 2>3:
         print(666)

        b,if     else

                name = input('>>>')

                if name == 'ghl'

                print('hehe')

                else:

                print(666)

        c,if elif  elif 

                num = int(input('>>>'))

                if num == 6:

                    print('吃飯')

                elif num == 4:

                    print('回家')

                elif num == 2:

                    print('玩')

        d,if elif  elif  else

                num = int(input('>>>'))

                if num == 6:

                    print('吃飯')

                elif num == 4:

                    print('回家')

                elif num == 2:

                    print('玩')

                else:

                    print('其他')

        e,if 嵌套

where:邏輯情況出現(xiàn)很多

流程控制語句while:

    why:用到循環(huán)的地方

    what:流程控制語句while

    how:

        1,基本結(jié)構(gòu):

            while 條件:

                循環(huán)體

        2,循環(huán)舉例:

            flag = True

             while flag:

                print(111)

                print(222)

                    flag = False

        3,終止循環(huán)

                a,條件不成立

                b,break

                c,系統(tǒng)命令quit()

        break:循環(huán)中只要遇到break就直接跳出循環(huán)

        continue:遇到continue跳出本次循環(huán),繼續(xù)下次循環(huán)

        while....else.....只要while循環(huán)被break打斷,則不走else程序