string.count() only tells me there are N instances of the string; it does not
say where they begin and end, as does re.finditer.
Feb 27, 2023, 16:20 by bobmellow...@gmail.com:
> Would string.count() work for you then?
>
> On Mon, Feb 27, 2023 at 5:16 PM Jen Kris via Python-list <>
> python-list@python.org> > wrote:
>
>>
>> I went to the re module because the specified string may appear more than
>> once in the string (in the code I'm writing). For example:
>>
>> a = "X - abc_degree + 1 + qq + abc_degree + 1"
>> b = "abc_degree + 1"
>> q = a.find(b)
>>
>> print(q)
>> 4
>>
>> So it correctly finds the start of the first instance, but not the second
>> one. The re code finds both instances. If I knew that the substring
>> occurred only once then the str.find would be best.
>>
>> I changed my re code after MRAB's comment, it now works.
>>
>> Thanks much.
>>
>> Jen
>>
>>
>> Feb 27, 2023, 15:56 by >> c...@cskk.id.au>> :
>>
>> > On 28Feb2023 00:11, Jen Kris <>> jenk...@tutanota.com>> > wrote:
>> >
>> >> When matching a string against a longer string, where both strings have
>> spaces in them, we need to escape the spaces.
>> >>
>> >> This works (no spaces):
>> >>
>> >> import re
>> >> example = 'abcdefabcdefabcdefg'
>> >> find_string = "abc"
>> >> for match in re.finditer(find_string, example):
>> >> print(match.start(), match.end())
>> >>
>> >> That gives me the start and end character positions, which is what I
>> want.
>> >>
>> >> However, this does not work:
>> >>
>> >> import re
>> >> example = re.escape('X - cty_degrees + 1 + qq')
>> >> find_string = re.escape('cty_degrees + 1')
>> >> for match in re.finditer(find_string, example):
>> >> print(match.start(), match.end())
>> >>
>> >> I’ve tried several other attempts based on my reseearch, but still no
>> match.
>> >>
>> >
>> > You need to print those strings out. You're escaping the _example_
>> string, which would make it:
>> >
>> > X - cty_degrees \+ 1 \+ qq
>> >
>> > because `+` is a special character in regexps and so `re.escape` escapes
>> it. But you don't want to mangle the string you're searching! After all, the
>> text above does not contain the string `cty_degrees + 1`.
>> >
>> > My secondary question is: if you're escaping the thing you're searching
>> _for_, then you're effectively searching for a _fixed_ string, not a
>> pattern/regexp. So why on earth are you using regexps to do your searching?
>> >
>> > The `str` type has a `find(substring)` function. Just use that! It'll be
>> faster and the code simpler!
>> >
>> > Cheers,
>> > Cameron Simpson <>> c...@cskk.id.au>> >
>> > --
>> > >> https://mail.python.org/mailman/listinfo/python-list
>> >
>>
>> --
>> >> https://mail.python.org/mailman/listinfo/python-list
>>
>
>
> --
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> Bob van der Poel ** Wynndel, British Columbia, CANADA **
> EMAIL: > b...@mellowood.ca
> WWW: > http://www.mellowood.ca
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