{:d} parsing ' 0' is wrong

[chengdi1988]

from parse import parse

parse('{a:d}','    0') # more than one blank before zero
# expect a==0
# result: None

[jonathangjertsen]

That is the expected behaviour. Remember that parse is intended to be the inverse of format, and there is no x such that format('{a:d}', x) returns a string that is left-padded with spaces. Therefore the corresponding call to parse must return None.

To match an arbitrary number of spaces in front, you could either use a regex of strip the string before passing it to parse.

BTW, parse does provide a result if you set the width specifier in the format string to any positive number at all:

>>> parse('{a:4d}', '    0')
<Result () {'a': 0}>
>>> parse('{a:1d}', '    0')
<Result () {'a': 0}>
>>> parse('{a:1000d}', '    0')
<Result () {'a': 0}>

But that's obviously a bug, so I wouldn't rely on it.