if在许多语言中都有 else是条件选择组合，但python中使用else的地方更多，如循环for或while。

下面简单介绍一下for-else while-else组合

在循环组合中执行else的情况下，循环正常结束(即不使用break退出)。以下代码:

numbers=[1，2，3，4，5]
forninnumbers:
if(n>5):
print('thevalueis%d'%(n))
break
else:
print('theforloopdoesnotendwithbreak')

i=0
while(numbers[i]<5):
print('theindex%dvalueis%d'%(i,numbers[i]))
if(numbers[i]<0):
break
i=i+1
else:
print('theloopdoesnotendwithbreak')

numbers=[1,2,3,4,5]
forninnumbers:
if(n>5):
print('thevalueis%d'%(n))
break
else:
print('theforloopdoesnotendwithbreak')

i=0
while(numbers[i]<5):
print('theindex%dvalueis%d'%(i,numbers[i]))
if(numbers[i]<0):
break
i=i+1
else:
print('theloopdoesnotendwithbreak')

结果如下：

C:\Python27>python.exefor_else.py
theforloopdoesnotendwithbreak
theindex0valueis1
theindex1valueis2
theindex2valueis3
theindex3valueis4
theloopdoesnotendwithbreak