Python基础二：条件和循环

判断语句
  1. if else 
    1     str = "a"
2     if str == "a":
3         print "a"
4     else:
5         print "b"
  2. if elif else 
    1     score = 70
2     if score > 90:
3         print ">90"
4     elif score > 70:
5         print ">70"
6     elif score >= 60:
7         print ">=60"
8     else:
9         print "<60"
  3. 不支持switch
循环语句
  • while 
    1     count = 0
2     while(count < 9):
3         print "The count is:", count
4         count = count + 1
5     print "Good bye!"
  • while else 
    1     count = 0
2     while count < 5:
3        print count, " is  less than 5"
4        count = count + 1
5     else:
6        print count, " is not less than 5"
  • for & for else:    else 中的语句会在循环正常执行完（即 for 不是通过 break 跳出而中断的）的情况下执行
  • 关键字 continue ,break 同其他语言
  • pass 空语句，为了保持程序结构的完整性，作为占位语句 
    1     tmp = 'y'
2     if tmp == 'y':
3         pass
4     else:
5         print 'x'

     

posted on 2017-03-05 16:38  Liz-  阅读(143)  评论(0)    收藏  举报