Thanks Jean for the comprehensive explanation. It is very helpful.
On Saturday, 31 July 2021 at 1:14:01 pm UTC-4 jj wrote:
> Hi Howard,
>
> Here is a commented version of your regular expression.
>
> (?x) (?# Allow whitespace and comments.
> )
> ( (?# Opening of capture 1.
> )
> . (?# Any single character.
> )
> ) (?# Closing of capture 1.
> )
> (?! (?# Opening negative lookahead assertion.
> )
> [^(]* (?# Zero or more characters that are not a opening
> parenthesis. )
> \) (?# A closing parenthesis.
> )
> ) (?# Closing negative lookahead assertion.
> )
>
> (?!...) is a Negative lookahead assertion.
> It basically says: find occurrences of 'this' that are not followed by
> 'that' but don't include the 'not that' in the match –– hence the
> 'lookahead'.
>
> For a detailed explanation check the *excellent* grep documentation in *menu
> Help > BBEdit Help > Grep Reference* link.
>
> So that says:
> "Any single character that is not followed by zero or more characters that
> are not the opening parenthesis, followed by a closing parenthesis."
>
> The double negation makes it difficult to fathom.
>
> The negative lookahead assertion says: skip any match that is followed by
> '...)' where ... are zero of more not '('.
> The digits of the first line are not followed by '...)' -> match.
> The first character of the second line '(' is followed by '10)' -> skip
> The second character of the second line '1' is followed by '0)' -> skip
> The third character of the second line '0' is followed by ')' -> skip
> The fourth character of the second line ')' is not followed by '...)' ->
> match
> ...
>
> A simpler regular expression that will give the same result (and probably
> be more performant) is:
>
> (\([^\)]*\)|\d)
>
> "Match any parentheses block or any single digits outside of parentheses
> blocks."
>
> HTH
>
> Jean Jourdain
>
>
> On Saturday, July 31, 2021 at 6:52:48 PM UTC+2 TJ Luoma wrote:
>
>>
>> Try pasting it into https://regexr.com
>>
>> That's what I usually use to translate regex into English :-)
>>
>>
>>
>> On Sat, Jul 31, 2021 at 10:20 AM Howard <[email protected]> wrote:
>>
>>> Can someone explain how the REGEX code below works?
>>> *(.)(?![^(]*\))*
>>>
>>> I know it looks for digits, including two-digit numbers in parentheses,
>>> and extracts them and inserts a space after each one, but I do not know how
>>> the code starting with *(?* works.
>>>
>>> Here is sample data for it:
>>> 010000000
>>> (10)1140006x
>>> 002200010
>>> 00000(11)01x
>>> 311200
>>>
>>> Here is output:
>>> 0 1 0 0 0 0 0 0 0
>>> (10) 1 1 4 0 0 0 6 x
>>> 0 0 2 2 0 0 0 1 0
>>> 0 0 0 0 0 (11) 0 1 x
>>> 3 1 1 2 0 0
>>>
>>>
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>>
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