optparse_example.py

python optparse_example.py

#!/usr/bin/env python
# Author: Greg Caporaso (gregcaporaso@gmail.com)
# optparse_template.py

""" Description
File created on 01 Aug 2009.

Code published via http://blog.caporaso.us.
Feel free to incorporate this code in your work. If
 it turns out to be helpful, please considering linking back to my
 blog post in a comment, for example: 
 
 Code modified from:
 http://blog.caporaso.us/2009/08/python-optparse-example-part-1.html

"""

from optparse import OptionParser

def parse_command_line_parameters():
    """ Parses command line arguments """
    usage = 'usage: %prog [options] output_filepath'
    version = 'Version: %prog 0.1'
    parser = OptionParser(usage=usage, version=version)

    # A binary 'verbose' flag
    parser.add_option('-v','--verbose',action='store_true',\
        dest='verbose',help='Print information during execution -- '+\
        'useful for debugging [default: %default]')

    # An example string option
    parser.add_option('-s','--string_to_write',action='store',\
          type='string',dest='string_to_write',help='a string to write to '+\
          'file [default: %default]')

    # An example int option
    parser.add_option('-i','--int_value',action='store',\
          type='int',dest='int_value',help='an integer value to store '+\
          '[default: %default]')

    # Set default values here if they should be other than None
    parser.set_defaults(verbose=False,\
     string_to_write="Some example input.")

    opts,args = parser.parse_args()
    num_args = 1
    if len(args) != num_args:
        parser.error('A single filepath is required.')

    return opts,args


if __name__ == "__main__":
    opts,args = parse_command_line_parameters()
    verbose = opts.verbose
    
    if verbose:
        print 'Writing file: %s.' % args[0]

    f = open(args[0],'w')
    f.write('%s\n' % opts.string_to_write)
    if opts.int_value != None:
        f.write('%d\n' % opts.int_value)
    f.close()
    
    if verbose:
        print 'File written.'