sys.argv[]的使用详解

sys.startswith() 是用来判断一个对象是以什么开头的，比如在python命令行输入“'abc'.startswith('ab')”就会返回True

以下实例参考:

#!/usr/local/bin/env python

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,
f.close()

print "sys.argv[0]---------",sys.argv[0]
print "sys.argv[1]---------",sys.argv[1]
print "sys.argv[2]---------",sys.argv[2]
# 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)

执行结果:# python test.py --version help
sys.argv[0]--------- test.py
sys.argv[1]--------- --version
sys.argv[2]--------- help
Version 1.2

注意:sys.argv[1][2:]表示从第二个参数，从第三个字符开始截取到最后结尾，本例结果为:version