Customize help output from optparse (or argparse)

[Thorsten Kampe]

Hi,

I'm using optparse for a little Python script.

1. The output from "--help" is:
"""
Usage: script.py <arg>

script.py does something

Options:
-h, --help show this help message and exit
"""

I would prefer to have the description before the usage, like...
"""
script.py does something

Usage: script.py <arg>

Options:
-h, --help show this help message and exit
"""

2. The output from "--doesnotexit" is:
"""
Usage: script.py <arg>

script.py: error: no such option: --doesnotexist
"""

I would prefer to have the error first, then the usage and additionally
the options, like...
"""
script.py: error: no such option: --doesnotexist

Usage: script.py <arg>

Options:
-h, --help show this help message and exit
"""

Is that possible with either optparse or the "new kid on the block"
argparse. If so how?

Thorsten

 

[Thomas 'PointedEars' Lahn]

I'm using optparse for a little Python script.

1. The output from "--help" is:
"""
Usage: script.py <arg>

script.py does something

Options:
-h, --help show this help message and exit
"""

I would prefer to have the description before the usage, like...
"""
script.py does something

Usage: script.py <arg>

Options:
-h, --help show this help message and exit
"""

2. The output from "--doesnotexit" is:
"""
Usage: script.py <arg>

script.py: error: no such option: --doesnotexist
"""

I would prefer to have the error first, then the usage and additionally
the options, like...
"""
script.py: error: no such option: --doesnotexist

Usage: script.py <arg>

Options:
-h, --help show this help message and exit
"""

Is that possible with either optparse or the "new kid on the block"
argparse. If so how?

You can easily have #1 with optparse.OptionParser(usage="…")¹, but optparse
is deprecated in favor of argparse.ArgumentParser. I do not think you can
have #2 with either optparse or argparse: OptionParser() would print the
error message last, and ArgumentParser() would not print the description
on error. Subclassing ArgumentParser might be feasible, though.

______
¹ <http://PointedEars.de/devel/tools/text/odfinfo/>

 

[Karim]

You can easily have #1 with optparse.OptionParser(usage="…")¹, but optparse
is deprecated in favor of argparse.ArgumentParser. I do not think you can
have #2 with either optparse or argparse: OptionParser() would print the
error message last, and ArgumentParser() would not print the description
on error. Subclassing ArgumentParser might be feasible, though.

______
¹<http://PointedEars.de/devel/tools/text/odfinfo/>

Please find documentation to configure help in ArgumentParser BUT for
argparse module:

- HelpFormatter, RawDescriptionHelpFormatter, RawTextHelpFormatter,
50 ArgumentDefaultsHelpFormatter -- Formatter classes which
51 may be passed as the formatter_class= argument to the
52 ArgumentParser constructor. HelpFormatter is the default,
53 RawDescriptionHelpFormatter and RawTextHelpFormatter tell
the parser
54 not to change the formatting for help text, and
55 ArgumentDefaultsHelpFormatter adds information about
argument defaults
56 to the help.

So It seems easy to a different pass formatter_class to ArgumentParser.
You can inherite
from HelpFormater class but you have to know the implementation details:
File is located at <python install>/lib/python2.7/argparse.py

Cheers
Karim

 

[Thorsten Kampe]

* Thomas 'PointedEars' Lahn (Thu, 12 May 2011 22:22:20 +0200)

I'm using optparse for a little Python script.

1. The output from "--help" is:
"""
Usage: script.py <arg>

script.py does something

Options:
-h, --help show this help message and exit
"""

I would prefer to have the description before the usage, like...
"""
script.py does something

Usage: script.py <arg>

Options:
-h, --help show this help message and exit
"""
[...]
Is that possible with either optparse or the "new kid on the block"
argparse. If so how?

You can easily have #1 with optparse.OptionParser(usage="…")¹, but optparse
is deprecated in favor of argparse.ArgumentParser.

I'm already using usage. That's where optparse has it from. Putting the
usage message into the description and vice versa is of course not a
viable way to go.

Thorsten