Re: Regular expression for "key = value" pairs
I extracted an isolated problem from a slightly more complex situation, that's why I'm using REs. Thank you all for your help, my problem is now solved. -- http://mail.python.org/mailman/listinfo/python-list
Re: Regular expression for "key = value" pairs
André writes:
> How about the following:
>
> >>> s = 'a=b,c=d'
> >>> t = []
> >>> for u in s.split(','):
> ... t.extend(u.split('='))
s = 'a = b = c, d = e'
=> ['a ', ' b ', ' c', ' d ', ' e']
Ugh.
-- [mdw]
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Re: Regular expression for "key = value" pairs
Ciccio writes:
> suppose I have:
>
> s='a=b, c=d'
>
> and I want to extract sub-strings a,b,c and d from s (and in general
> from any longer list of such comma separated pairs).
[...]
> In [12]: re.findall(r'(.+)=(.+)', s)
> Out[12]: [('a=b, c', 'd')]
I think there are two logically separate jobs here: firstly, extracting
the comma-separated pairs, and secondly parsing the individual pairs.
If you want the extra problem of dealing with regular expressions, this
seems to be the way to do it.
R_PAIR = re.compile(r'''
^\s*
([^=\s]|[^=\s][^=]*[^=\s])
\s*=\s*
(\S|\S.*\S)
\s*$
''', re.X)
def parse_pair(pair):
m = R_PAIR.match(pair)
if not m:
raise ValueError, 'not a `KEY = VALUE\' pair'
return m.groups([1, 2])
The former is even easier.
R_COMMA = re.compile(r'\s*,\s*')
kvs = [parse_pair(p) for p in R_COMMA.split(string)]
Apply gold-plating to taste.
But actually, it's much easier to avoid messing with regular expressions
at all.
def parse_pair(pair):
eq = pair.index('=')
return pair[:eq].strip(), pair[eq + 1:].strip()
kvs = [parse_pair(p) for p in string.split(',')]
-- [mdw]
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Re: Regular expression for "key = value" pairs
2010/12/22 Ciccio :
> Hi all,
> suppose I have:
>
> s='a=b, c=d'
>
> and I want to extract sub-strings a,b,c and d from s (and in general from
> any longer list of such comma separated pairs).
> Some failed attempts:
>
> In [12]: re.findall(r'(.+)=(.+)', s)
> Out[12]: [('a=b, c', 'd')]
>
> [...]
> Thanks for your help,
> francesco.
> --
> http://mail.python.org/mailman/listinfo/python-list
>
Hi,
I am not sure, the regular expressions are best suited for this task,
but if you have a predictable simple parameter list (with ho
recursion, escaping commas or equal signs etc.), it might be viable;
how about e.g. this pattern?
>>> re.findall(r'([^=\s,]+)=([^=\s,]+)', s)
[('a', 'b'), ('c', 'd')]
>>>
vbr
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Re: Regular expression for "key = value" pairs
On Wednesday, December 22, 2010 12:22:22 PM UTC-4, Francesco Napolitano wrote:
> Hi all,
> suppose I have:
>
> s='a=b, c=d'
>
> and I want to extract sub-strings a,b,c and d from s (and in general
> from any longer list of such comma separated pairs).
> Some failed attempts:
>
> In [12]: re.findall(r'(.+)=(.+)', s)
> Out[12]: [('a=b, c', 'd')]
>
> In [13]: re.findall(r'(.+?)=(.+)', s)
> Out[13]: [('a', 'b, c=d')]
>
> In [14]: re.findall(r'(.+)=(.+)*', s)
> Out[14]: [('a=b, c', 'd')]
>
> In [15]: re.findall(r'(.+)=(.+),', s)
> Out[15]: [('a', 'b')]
>
> In [16]: re.findall(r'(.+)=(.+),?', s)
> Out[16]: [('a=b, c', 'd')]
>
How about the following:
>>> s = 'a=b,c=d'
>>> t = []
>>> for u in s.split(','):
... t.extend(u.split('='))
...
>>> t
['a', 'b', 'c', 'd']
HTH,
André
> Thanks for your help,
> francesco.
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Regular expression for "key = value" pairs
Hi all,
suppose I have:
s='a=b, c=d'
and I want to extract sub-strings a,b,c and d from s (and in general
from any longer list of such comma separated pairs).
Some failed attempts:
In [12]: re.findall(r'(.+)=(.+)', s)
Out[12]: [('a=b, c', 'd')]
In [13]: re.findall(r'(.+?)=(.+)', s)
Out[13]: [('a', 'b, c=d')]
In [14]: re.findall(r'(.+)=(.+)*', s)
Out[14]: [('a=b, c', 'd')]
In [15]: re.findall(r'(.+)=(.+),', s)
Out[15]: [('a', 'b')]
In [16]: re.findall(r'(.+)=(.+),?', s)
Out[16]: [('a=b, c', 'd')]
Thanks for your help,
francesco.
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