python学习笔记之sys.argv

sys.argv是接收的参数的列表 []
比如这段代码名字叫做test.py
运行python test.py 192.168.0.1  test.txt
sys.argv[0]  ----test.py
sys.argv[1]  ----192.168.0.1
sys.argv[2]  ----test.txt

简明python教程中的例子

例14.1 使用sys.argv#!/usr/bin/python
# Filename: cat.py

import sys

def readfile(filename):
'''Print a file to the standard output.'''
f = file(filename)
while True:
line = f.readline()
if len(line) == 0:
break
print line, # notice comma
f.close()

# Script starts from here
if len(sys.argv) < 2:
print 'No action specified.'
sys.exit()

if sys.argv[1].startswith('--'):
option = sys.argv[1][2:]
# fetch sys.argv[1] but without the first two characters
if option == 'version':
print 'Version 1.2'
elif option == 'help':
print '''\
This program prints files to the standard output.
Any number of files can be specified.
Options include:
--version : Prints the version number
--help : Display this help'''
else:
print 'Unknown option.'
sys.exit()
else:
for filename in sys.argv[1:]:
readfile(filename)
输入命令

python cat.py --help

sys.argv[0]是cat.py
sys.argv[1]是--help
sys.argv[1][0]是-
sys.argv[1][1]是-
sys.argv[1][2]是h
sys.argv[1][1:]是-help
sys.argv[1][2:]是除了前两个字符的sys.argv[1],本例中是help
sys.argv[1:]是['--help']