一、while循环
例1
count = 0
while (count < 9):
print 'The count is:', count
count = count + 1
print "Good bye!"
运行结果：
The count is: 0
The count is: 1
The count is: 2
The count is: 3
The count is: 4
The count is: 5
The count is: 6
The count is: 7
The count is: 8
例2 （while…else句式）
count = 0
while count < 5:
print count, " is less than 5"
count = count + 1
else:
print count, " is not less than 5"
运行结果：
0 is less than 5
1 is less than 5
2 is less than 5
3 is less than 5
4 is less than 5
5 is not less than 5
二、for循环
例3
# -*- coding: UTF-8 -*-
for letter in 'Python': # 第一个实例
print '当前字母 :', letter
fruits = ['banana', 'apple', 'mango']
for fruit in fruits: # 第二个实例
print '当前水果 :', fruit
print "Good bye!"
运行结果：
当前字母 : P
当前字母 : y
当前字母 : t
当前字母 : h
当前字母 : o
当前字母 : n
当前水果 : banana
当前水果 : apple
当前水果 : mango
Good bye!
三、Pass语句
例4
# -*- coding: UTF-8 -*-
# 输出 Python 的每个字母
for letter in 'Python':
if letter == 'h':
pass
print '这是 pass 块'
print '当前字母 :', letter
print "Good bye!"
运行结果：
当前字母 : P
当前字母 : y
当前字母 : t
这是 pass
