The code I sent is correct, and it runs here. Maybe you received it with a
carriage return removed, but on my copy after posting, it is correct:
example = 'X - abc_degree + 1 + qq + abc_degree + 1'
find_string = re.escape('abc_degree + 1')
for match in re.finditer(find_string, example):
print(match.start(), match.end())
One question: several people have made suggestions other than regex (not your
terser example with regex you shown below). Is there a reason why regex is not
preferred to, for example, a list comp? Performance? Reliability?
Feb 27, 2023, 18:16 by [email protected]:
> Jen,
>
> Can you see what SOME OF US see as ASCII text? We can help you better if we
> get code that can be copied and run as-is.
>
> What you sent is not terse. It is wrong. It will not run on any python
> interpreter because you somehow lost a carriage return and indent.
>
> This is what you sent:
>
> example = 'X - abc_degree + 1 + qq + abc_degree + 1'
> find_string = re.escape('abc_degree + 1') for match in
> re.finditer(find_string, example):
> print(match.start(), match.end())
>
> This is code indentedproperly:
>
> example = 'X - abc_degree + 1 + qq + abc_degree + 1'
> find_string = re.escape('abc_degree + 1')
> for match in re.finditer(find_string, example):
> print(match.start(), match.end())
>
> Of course I am sure you wrote and ran code more like the latter version but
> somewhere in your copy/paste process, ....
>
> And, just for fun, since there is nothing wrong with your code, this minor
> change is terser:
>
>>>> example = 'X - abc_degree + 1 + qq + abc_degree + 1'
>>>> for match in re.finditer(re.escape('abc_degree + 1') , example):
>>>>
> ... print(match.start(), match.end())
> ...
> ...
> 4 18
> 26 40
>
> But note once you use regular expressions, and not in your case, you might
> match multiple things that are far from the same such as matching two
> repeated words of any kind in any case including "and and" and "so so" or
> finding words that have multiple doubled letter as in the stereotypical
> bookkeeper. In those cases, you may want even more than offsets but also show
> the exact text that matched or even show some characters before and/or after
> for context.
>
>
> -----Original Message-----
> From: Python-list <[email protected]> On
> Behalf Of Jen Kris via Python-list
> Sent: Monday, February 27, 2023 8:36 PM
> To: Cameron Simpson <[email protected]>
> Cc: Python List <[email protected]>
> Subject: Re: How to escape strings for re.finditer?
>
>
> I haven't tested it either but it looks like it would work. But for this
> case I prefer the relative simplicity of:
>
> example = 'X - abc_degree + 1 + qq + abc_degree + 1'
> find_string = re.escape('abc_degree + 1') for match in
> re.finditer(find_string, example):
> print(match.start(), match.end())
>
> 4 18
> 26 40
>
> I don't insist on terseness for its own sake, but it's cleaner this way.
>
> Jen
>
>
> Feb 27, 2023, 16:55 by [email protected]:
>
>> On 28Feb2023 01:13, Jen Kris <[email protected]> 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).
>>>
>>
>> Sure, but writing a `finditer` for plain `str` is pretty easy (untested):
>>
>> pos = 0
>> while True:
>> found = s.find(substring, pos)
>> if found < 0:
>> break
>> start = found
>> end = found + len(substring)
>> ... do whatever with start and end ...
>> pos = end
>>
>> Many people go straight to the `re` module whenever they're looking for
>> strings. It is often cryptic error prone overkill. Just something to keep in
>> mind.
>>
>> Cheers,
>> Cameron Simpson <[email protected]>
>> --
>> https://mail.python.org/mailman/listinfo/python-list
>>
>
> --
> https://mail.python.org/mailman/listinfo/python-list
>
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