python學習筆記之sys.argv

sys.argv是接收的參數的列表 []
比如這段代碼名字叫做test.py 
運行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

簡明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)

輸入命令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:]是除了前兩個字符的sys.argv[1],本例中是help
sys.argv[1:]是['--help']