Python command-line parameter parsing example application __python

one, sys.argv[]A list of strings containing command-line arguments to get parameters by subscript.
For example:
#!/usr/bin/python
# Filename:using_sys.py
Import Sys

print ' command line arguments are: '
For I in SYS.ARGV:
Print I

print ' \n\nthe pythonpath is ', Sys.path, ' \ n '
Print Argv[1]

Argv[0] Represents the path of the file itself. Of course, agv[] can also hold multiple values
Second, getoptUsed to extract command-line options and parameters, which is sys.argv.
command-line options make the program more flexible in its parameters. Supports short option mode and long option mode.

Import getopt
#python scriptname.py-f ' Hello '--directory-prefix=/home-t--form at ' a ' B '

Shortargs = ' F:t '
Longargs = [' directory-prefix= ', ' format ', '--f_long= ']
opts, args = Getopt.getopt (sys.argv[1:], Shortargs, Longargs)

The format of the getopt function is getopt.getopt ([command line argument list], short option, [Long option list])
The colon after the short option name (:) indicates that the option must have additional parameters.
The equal sign (=) after the long option name indicates that the option must have additional parameters.
Return to opts and args.

OPTs is a tuple of parameter options and their value ('-f ', ' Hello '), ('-t ', ', '), ('--format ', '), ('--directory-prefix ', '/home '))
Args is a command line input other than a useful parameter (' A ', ' B ')
Then traverse opts to get all the command-line options and their corresponding parameters.

Traversal opts can get the options and parameters of all commands,
For opt, Val in opts:
If opt in (' f ', '--f_long '):
Pass
If .....


Analyze different parameters and do different processing. Generally, the list of option arguments is printed as a help option.
The typical use of getopt is also given in the Python documentation:Import getopt, sys

def main ():
Try
opts, args = Getopt.getopt (sys.argv[1:], "ho:v", ["Help", "output="])
Except Getopt. Getopterror, err:
# Print Help information and exit:
Print str (ERR) # 'll print something like ' option-a not recognized '
Usage ()
Sys.exit (2)
Output = None
verbose = False
For O, a in opts:
If o = = "-V":
verbose = True
Elif o in ("H", "--help"):
Usage ()
Sys.exit ()
Elif o in ("O", "--output"):
Output = a
Else
Assert False, "unhandled option"
# ...

if __name__ = = "__main__":
Main ()
Iv. Example ApplicationA simple example is shown below:
Import getopt, sys


opts, args = Getopt.getopt (sys.argv[1:], "Hi:o:", ["Help", "input=", "output="])


def usage ():
Print Sys.argv[0] + '-I inputfile-o outputfile '
Print Sys.argv[0] + '-h #get help Info '


Input_file, output_file = ', '
For OP, value in opts:
If op = = ' I ' or op = '--input ':
Input_file = value
Elif op = = ' O ' or op = '--output ':
Output_file = value
Elif op = = '-h ':
Usage ()
Sys.exit ()


You can run on the command line in the following ways:
$ python test.py-i./input.txt-o./output.txt
$ python test.py--input=./input.txt-o./output.txt
$ python test.py-i./input.txt--output=./output.txt
$ python test.py--input=./input.txt--output=./output.txt
$ python test.py-h