Option multiplicity with docopt

Question

I would like to using docopt for parsing a command line that can receive the same option multiple times. Could somebody explain me how to do it?

A test example:

#!/usr/bin/env python

"""
Test program.

Usage:
    test.py -v

Options:
    -v  Flag that should be counted
"""

import docopt
print docopt.docopt(__doc__)

If I run this with test.py -v, I get:

{'-v': True}

Where as if I run this with test.py -vv, it displays the usage message (indicating the command line is not valid).

I'd like to tweak the option documentation so that docopt returns me:

{'-v': 1}

When only 1 -v was passed and:

{'-v': 3}

If, say, the user passed -vvv. This is pretty much the same functionality the count action in argparse.

score 7 · Accepted Answer · answered Aug 28 '13 at 12:18

7

After digging the docopt (closed) issue list, I have found that the right way to represent this would be:

#!/usr/bin/env python

"""
Test program.

Usage:
    test.py (-v ...)

Options:
    -v  Flag that should be counted
"""

import docopt
print docopt.docopt(__doc__)

That is, one must use the symbol "..." to signify that an option may appear multiple times. In this case, the option will be correctly counted. If the above program is called with test.py -vvv, it will correctly print:

{'-v': 3}

The symbol "..." can also be used with arguments and options that take arguments pretty much the same way, just hit the link above for an example of that.

answered Aug 28 '13 at 12:18

André Anjos

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And this can be extended to passing a list as an argument – Kaushik Ghose May 09 '14 at 15:01
@KaushikGhose Can a list be passed like this: `--input-files a.csv b.csv --output-files c.csv d.csv'? What do you mean exactly? – The Unfun Cat Sep 16 '15 at 11:44
@TheUnfunCat It would be more like: `--input-files a.csv --input-files b.csv --output-files c.csv --output-files d.csv` – Kaushik Ghose Sep 21 '15 at 14:07
Thanks. That means globbing is not possible then (even click does not allow for variable length options that way...) – The Unfun Cat Sep 21 '15 at 15:07

score 2 · Answer 2 · answered May 09 '14 at 15:05

(This is just a comment to the above, but would get awkward as a comment.)

And this can be extended to passing a list as an argument:

"""
Usage:
program (--opt=OPT ...)

Options:
  --opt=OPT    An option that can be specified multiple times to form a list
"""

import docopt

print docopt.docopt(__doc__)

And we run this as

python test.py --opt=first_option
{'--opt': ['first_option']}

python test.py --opt=first_option --opt="second in line"
{'--opt': ['first_option', 'second in line']}

And so on.

Option multiplicity with docopt

2 Answers2