Python parse empty string

Question

I'm using the parse library and ran into surprising (to me) functionality: it does not match empty strings:

>>> from parse import parse
>>> parse('hi "{}"', 'hi "everybody"')
<Result ('everybody',) {}>
>>> parse('hi "{}"', 'hi ""')
>>>

Is there a way, using parse, to get it to match any string between "" in the same way that re does:

>>> from re import match
>>> match('hi "(.*)"', 'hi "everybody"').groups()
('everybody',)
>>> match('hi "(.*)"', 'hi ""').groups()
('',)

@mattm The point is that the string between the "s is empty. — Barry
– Barry, Commented Dec 30, 2014 at 20:07
No. That's what I'm trying to say. There is no string between the "'s, just as there is no string between the h and the i in 'hi'. — dursk
– dursk, Commented Dec 30, 2014 at 20:36
@mattm I haven't the slightest idea what it is you're trying to say. I know there's no string between the "s. I want parse to give me back an empty string in that case. — Barry
– Barry, Commented Dec 30, 2014 at 20:52

David K. Hess · Accepted Answer · 2014-12-30 20:20:16Z

5

Use a custom type conversion:

from parse import parse
def zero_or_more_string(text):
    return text

zero_or_more_string.pattern = r".*"
parse('hi "{:z}"', 'hi ""', { "z": zero_or_more_string })

and you'll get this:

<Result ('',) {}>

answered Dec 30, 2014 at 20:20

David K. Hess

17.3k2 gold badges53 silver badges77 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Python parse empty string

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related