Example analysis of SYS.ARGV parameter usage in Python

The examples in this article describe the use of sys.argv parameters in Python. Share to everyone for your reference. The specific analysis is as follows:

In the process of learning Python, I never understood the meaning of sys.argv[], though I knew it was a command line argument, but it was a bit of a blur.

Today, a good study of a, finally is Taichetaiwu.

Sys.argv[] is used to get command line arguments, Sys.argv[0] represents the code itself file path, so the parameters starting from 1, the following two examples illustrate:

1. A simple example of using sys.argv[]

Import Sys,osos.system (sys.argv[1])

This example Os.system receive command line arguments, run parameter directives, save as sample1.py, command line with parameters run sample1.py Notepad, will open the Notepad program.

2, this example is a concise Python tutorial, understand it after you understand sys.argv[].

Import sysdef ReadFile (filename): #从文件中读出文件内容 ' Print a file to the standard output. ' f = file (filename) while true:line = F.readline () If Len (lines) = = 0:breakprint line, # Notice comma outputs each row of content F.close () # Scrip T starts from HEREif Len (SYS.ARGV) < 2:print ' No action specified. ' Sys.exit () if Sys.argv[1].startswith ('--'): option = S ys.argv[1][2:]# fetch sys.argv[1] but without the first and charactersif option = = ' Version ': #当命令行参数为--version, showing the revision number Prin T ' Version 1.2 ' elif option = = ' help ': #当命令行参数为--help When the content is displayed "This program prints files to the standard OUTPUT.A NY number of files can be specified. Options include:--version:prints The version number--help  : Display This "" Else:print ' Unknown option. ' Sys.exi T () else:for filename in sys.argv[1:]: #当参数为文件名时, passing in ReadFile, reading its contents ReadFile (filename)

Save the program as sample.py. Let's verify that:

command line with parameters run: Sample.py–version output is: Version 1.2

command line with parameters run: Sample.py–help output is: This program prints files ...

In the same directory as sample.py, the new a.txt Notepad file is: Test argv; command line with parameters run: sample.py a.txt, the output is a.txt file content: Test argv, here can also take a few parameters, The program will output the contents of the parameter file successively.

Hopefully this article will help you with Python programming.

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