#coding=utf-8
#!/usr/bin/python3

循环语句 while

n = 100

sum = 0 
counter = 1

while counter <= n:
    sum = sum + counter
    counter += 1
    pass
print("1 到%d之和为:%d" % (n,sum))


count = 0

while count < 5:
    print("count %d 小于 5" % count)
    count += 1
    pass
else:
    print("count %d 大于等于 5" % count)

    languages = ["c","C++","perl","python"]

循环语句for

sites = ["Baidu", "Google","Runoob","Taobao"]

for site in sites:
    if site == "Runoob":
        print("菜鸟教程!")
        break
    print("循环数据 " + site)
else:
    print("没有循环数据!")
print("完成循环!")


for i in range(5):
    print i

for i in range(5,9): 
     print i # 5 ,6,7,8 没到9

for i in range(0,10,2): # 2是步长（增量） 不写默认为1
    print i
for i in range(-10,-100,-30): # 间隔是-30
    print i

遍历数组

a = ["a","b","c","d","e","f","g"]

for i in range(len(a)):
    print("第%d个数为:%s" % (i + 1,a[i]))

a = list(range(100)) # 创建一个列表
# print a

break 和continue 语句及循环中的else子句

for letter in "runoob":
    if letter == "b":
        break
        print("当前字符是:" % letter)
    else:
        print letter
    
print "GoodBye!"

var1 = 10

while var1 > 0:
    #print("count %d 小于 5" % count)

    print("var1 == %d " % var1)
    var1 -= 1
    if var1 == 5:
        break
print "结束"

var2 = 10

while var2 > 0:
    # print("var2 == %d" % var2)

    var2 -= 1

    if var2 == 5: continue # 当变量为5时跳过这次循环 继续进行下一轮循环
    print("变量var2 == %s" % var2)


for n in range(2,10):
    for x in range(2,n):
        if n % x == 0:
            # print(n,"等于",x,"*",n / x)
            print("%d等于%d * %d" % (n,x, n/x))
            break
    else:
        print("%d是质数" % n)

## Python pass是空语句，是为了保持程序结构的完整性。

pass 不做任何事情，一般用做占位语句，如下实例

最小的类

class MyEmpty:
    pass

# while True:
#     pass

for letter in "runoob":
    if letter  == "o":
        pass
        print "执行pass块"
    print("当前字符是:%s" % letter)

print "good bye"