Python SYS.ARGV Usage Examples

This article mainly introduces Python sys.argv usages, sys.argv[] is used to get command-line arguments, Sys.argv[0] represents the file path of the code itself, others are used to indicate getting input parameters, the friends you need can refer to the

The SYS.ARGV variable is a list of strings. Specifically, SYS.ARGV contains a list of command-line arguments, that is, the arguments that are passed to your program using the command line.

Here, when we execute the Python using_sys.py we are arguments, we run the using_sys.py module using the Python command, followed by the contents being passed as arguments to the program. Python stores it in SYS.ARGV variables for us. Remember that the name of the script always sys.argv the first parameter of the list. So, here, ' using_sys.py ' is sys.argv[0], ' we ' are sys.argv[1, ' are ' is sys.argv[2 ' and ' arguments ' is sys.argv[3. Note that Python counts starting at 0, not starting at 1.

Sys.argv[] is used to get command-line arguments, Sys.argv[0] represents the file path of the code itself, such as "Python test.py-help" at the cmd command line, and Sys.argv[0] represents "test.py".

Sys.startswith () is used to determine what an object begins with, such as entering ' abc ' in the Python command line. StartsWith (' AB ') returns true

The following examples refer to:

The code is as follows:

#!/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 two characters

if option = = ' Version ':

print ' Version 1.2 '

elif option = = ' help ':

print ' "

This is prints files to the standard output.

Any number of the 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)

Execution result: # python test.py--version Help

The code is as follows:

Sys.argv[0]---------test.py

SYS.ARGV[1]-----------version

SYS.ARGV[2]---------Help

Version 1.2

Note: sys.argv[1][2:] represents from the second argument, from the third character to the end of the intercept, the result of this example is: Version