Why use argparse rather than optparse

Question

I noticed that the Python 2 7 documentation includes yet another command-line parsing module   In addition to getopt and optparse we now have argparse   Why has yet another command-line parsing module been created   Why should I use it instead of optparse   Are there new features that I should know about

User · Accepted Answer

As of python 2 7  optparse is deprecated  and will hopefully go away in the future   argparse is better for all the reasons listed on its original page  https   code google com archive p argparse      handling positional arguments supporting sub-commands allowing alternative option prefixes like   and   handling zero-or-more and one-or-more style arguments producing more informative usage messages providing a much simpler interface for custom types and actions   More information is also in PEP 389  which is the vehicle by which argparse made it into the standard library

User · Answer

The best source for rationale for a Python addition would be its PEP  PEP 389  argparse - New Command Line Parsing Module  in particular  the section entitled  Why aren t getopt and optparse enough

User · Answer

There are also new kids on the block    Besides the already mentioned deprecated optparse   DO NOT USE  argparse was also mentioned  which is a solution for people not willing to include external libs  docopt is an external lib worth looking at  which uses a documentation string as the parser for your input  click is also external lib and uses decorators for defining arguments   My source recommends  Why Click  python-inquirer For selection focused tools and based on Inquirer js  repo    If you need a more in-depth comparison please read this and you may end up using docopt or click  Thanks to Kyle Purdon

User · Answer

Why should I use it instead of   optparse  Are their new features I   should know about     Nicholas s answer covers this well  I think  but not the more  meta  question you start with      Why has yet another command-line   parsing module been created    That s the dilemma number one when any useful module is added to the standard library  what do you do when a substantially better  but backwards-incompatible  way to provide the same kind of functionality emerges   Either you stick with the old and admittedly surpassed way  typically when we re talking about complicated packages  asyncore vs twisted  tkinter vs wx or Qt       or you end up with multiple incompatible ways to do the same thing  XML parsers  IMHO  are an even better example of this than command-line parsers -- but the email package vs the myriad old ways to deal with similar issues isn t too far away either -    You may make threatening grumbles in the docs about the old ways being  deprecated   but  as long as you need to keep backwards compatibility  you can t really take them away without stopping large  important applications from moving to newer Python releases    Dilemma number two  not directly related to your question  is summarized in the old saying  the standard library is where good packages go to die     with releases every year and a half or so  packages that aren t very  very stable  not needing releases any more often than that  can actually suffer substantially by being  frozen  in the standard library    but  that s really a different issue

User · Answer

At first I was as reluctant as  fmark to switch from optparse to argparse  because     I thought the difference was not that huge  Quite some VPS still provides Python 2 6 by default    Then I saw this doc  argparse outperforms optparse  especially when talking about generating meaningful help message  http   argparse googlecode com svn trunk doc argparse-vs-optparse html  And then I saw  argparse vs  optparse  by  Nicholas  saying we can have argparse available in python  lt 2 7   Yep  I didn t know that before    Now my two concerns are well addressed  I wrote this hoping it will help others with a similar mindset

[python] Why use argparse rather than optparse?

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