python学习：函数传参数

#!/usr/bin/python

import sys

def isNum(s):
for i in s:
if i in '0123456789':
pass
else:
print "%s is not a number" %s
sys.exit()
else:
print "%s is a number" %s

isNum(sys.argv[1])

//函数判断是否为数字

执行结果：
python 12.py aa
aa is not a number
[root@web10 day02]# python 12.py 123
123 is a number
[root@web10 day02]# python 12.py 123d
123d is not a number

#!/usr/bin/python

import sys
import os

def isNum(s):
if s.isdigit():
return True
return False

for i in os.listdir('/proc'):
if isNum(i):
print i
#同样的效果 更加的简洁