python语法 之 循环迭代

# -*- coding:utf-8 -*-
#while 条件:
#    代码块11
#else:
#    代码块2

i=1
while i<=5:
print '第'+str(i)+'次输出'
i+=1 #语法没有i++
else:
print '完毕'

#for one in object:
#    代码块1
#    if 条件1:
#        break
#    if 条件2:
#        continue
#    else:
#        pass

nums=[1,2,3,4,5]
for num in nums:
print num
#
##所谓字典:由“键-值”组成的集合
#
dic = {'1':'a','2':'b'}
for key in dic:
print key,'----',dic[key]

#for循环遍历元祖：

tuple=[(1,2),(3,4)]
for a,b in tuple:
print a,b

#||

for (a,b) in tuple:
print a,b

for a in tuple:
print a

#迭代器
#任何类似的对象都被认为是可迭代的。迭代工具的内部工作都是在循环调用next方法，
#并且捕捉StopIteration异常来确定何时离开。

for readline in open('test.py'):
print readline

#iter()内置函数

many = [1,2,3,4,5]
one = iter(many)
print one.next();
print one.next();
print one.next();
print one.next();
#
##直接for循环
#
for one in iter(many):
print one

#九九乘法表

for i in range(1,10):
for j in range(1,i+1):
print (" ".join(["%d*%d=%d" %(j,i,i*j)]))

#并行迭代

names=['a','b']
ages=[1,2]

for i in range(len(names)):
print names[i],'----',ages[i]

#zip迭代是把两个序列“压缩”在一起，然后返回一个元祖的列表

for name,age in zip(names,ages):
print name,'-------',age

#编号迭代
for index,name in enumerate(names):
if 'a' in names:
names[index]='aaa'
print index,name
for name in names:
print name