Multiple lines in python argparse help display

Question

I\'m using argparse in Python2.7 and I would like to display multiple lines in the help text of an argument.

My codes look like this:

import argparse

         


        

Answer 1

The default help formatter re-wraps lines to fit your terminal (it looks at the COLUMNS environment variable to determine the output width, defaulting to 80 characters total).

From the formatter_class section:

By default, ArgumentParser objects line-wrap the description and epilog texts in command-line help messages.

Use the RawTextHelpFormatter class instead to indicate that you already wrapped the lines:

RawTextHelpFormatter maintains whitespace for all sorts of help text, including argument descriptions.

For your code that'd look like:

parser = argparse.ArgumentParser(description='details',
        usage='use "%(prog)s --help" for more information',
        formatter_class=argparse.RawTextHelpFormatter)

Do watch out you don't add too many newlines; triple-quoted strings include the newlines you leave in the string. As such you don't need the \n characters:

>>> import argparse
>>> parser = argparse.ArgumentParser(description='details',
...         usage='use "%(prog)s --help" for more information',
...         formatter_class=argparse.RawTextHelpFormatter)
>>> parser.add_argument('--argument', default=None,
...         help='''
...              First line
...              Second line
... 
...              More lines
...              ''')
_StoreAction(option_strings=['--argument'], dest='argument', nargs=None, const=None, default=None, type=None, choices=None, help='\n             First line\n             Second line\n\n             More lines\n             ', metavar=None)
>>> parser.print_help()
usage: use " --help" for more information

details

optional arguments:
  -h, --help           show this help message and exit
  --argument ARGUMENT  
                                    First line
                                    Second line

                                    More lines