dynamic command line options in python
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What it is.

dyn_options is an easy way to process command line options. It creates an options object, which has the command line flags as attributes. The value of the option object attribute is it's value provided on the command line.

It allows for defaults, as well as a way to check whether the option has been set.

Anything starting with a - or -- (i.e. a single or double dash) is considered a flag. Anything following a flag is concatenated until the next flag is encountered.

For example, '--opt4 hello world' will be converted to an attribute called opt4, which has a value of 'hello world'.

A single flag will have a corresponding attribute value of True or False.

How it is used.

Here is how an option object is created

    import dyn_options

    option = dyn_options.create_option(argv, option_defaults())

If you have defaults, option_defaults() should return a dictionary of key-value pairs.

The option object returned is immutable, so you can't reset the attribute values, nor can you add additional attributes. There's no error raised when you try either of these things.

An example

example.py has some sample code that you can use to play around with:

#!/usr/bin/env python

import sys

import dyn_options

def option_defaults() :
    return dict( [("opt1", "opt1_default"), ("help", False)])

def main(argv) :
    option = dyn_options.create_option(argv, option_defaults())
    print "using defaults :", option

    option = dyn_options.create_option(argv)
    print "no defaults :", option

if option.opt4 :
    print "opt4 is set :", option.opt4
else :
    print "opt4 is not set"

if __name__ == '__main__':

Here 's the out put for :

./example.py --opt2 --opt4 hello world

using defaults : options :
      #) help ==> False
      #) program ==> ./example.py
      #) opt4 ==> hello world
      #) opt1 ==> opt1_default
      #) opt2 ==> True
no defaults : options :
      #) program ==> ./example.py
      #) opt4 ==> hello world
      #) opt2 ==> True
opt4 is set : hello world

Here's the output for :

./example.py --opt1 new_value 

using defaults : options :
     #) help ==> False
     #) program ==> ./example.py
     #) opt1 ==> new_value
no defaults : options :
     #) program ==> ./example.py
     #) opt1 ==> new_value
opt4 is not set


Run install as a privileged user (or sudo install) from the command line.

This will create a subdirectory with the contents of the package as well as a build directory. This is then pushed to the site-packages directory by running python setup.py install

More information

See dyn_option_test.py for more examples.

See www.prognotes.com for a more elaborate description.


This is distributed under the BSD License. See the LICENSE file for details. Obviously the LICENSE needs to be included in any further distribution.