Regex to "normalize" usage of SPACE after . , : chars (and some exceptions)-CodePudding

I need to normalize some texts (product descriptions) in regard to the correct usage of .,,,: symbols (no space before and one space after)

The regex I've come up with is this:

$variation['DESCRIPTION'] = preg_replace('#\s*([:,.])\s*(?!<br />)#', '$1 ', $variation['DESCRIPTION']);

The problem is that this matches three cases it shouldn't touch:

Any decimal number, like 5.5
Any thousand separator, like 4,500
A "fixed" phrase in Greek, ό,τι
The ellipsis symbol, ...

Especially for the numeric exception, I know it can be achieved with some negative lookahead/lookbehind but unfortunately I can't combine them in my current pattern.

This is a fiddle for you to check (the cases that shouldn't be matched are in lines 2, 3, 4).

EDIT: I just realized that I'd need the pattern to also exclude ellipsis ... from the matches!

Any help will be very much appreciated! TIA

CodePudding user response：

You can add two lookaheads containing lookbehinds:

\s*([:,.])(?!(?<=ό,)τι)(?!(?<=\d.)\d)(?!\s*<br\s*/>)\s*

See the regex demo. Note that I also added \s* to the last lookahead and swapped it with the consuming \s* to fail the match if there is <br/> after any zero or more whitespaces after the :, , or ..

Details

\s* - zero or more whitespaces
([:,.]) - Group 1: a :, , or .
(?!(?<=ό,)τι) - fail the match if the next two chars are τι preceded with ό,
(?!(?<=\d.)\d) - fail the match if the next char is a digit preceded with a digit and any char (note that a . is enough since the [:,.] already match the char allowed/required, here, we just need to "jump" over that matched char)
(?!\s*<br\s*/>) - a negative lookahead that fails the match if there are zero or more whitespaces, <br, zero or more whitespaces, /> immediately to the right of the current location.
\s* - zero or more whitespaces.

CodePudding user response：

If Wiktor's lookaround-heavy pattern is too difficult for you to conceptualize/maintain/adapt, then perhap a match&ignore technique will be easier for you. Admittedly, Wiktor's pattern is optimized for performance.

Pattern:

~                        #starting pattern delimiter 
\s*                      #zero or more whitespaces
(?:                      #start non-capturing group #1
  (?:                    #start non-capturing group #2
    \.\d                 #float expression not requiring leading digits
    |                    #or
    \d{1,3}(?:,\d{3})    #number containing thousands separators
    |                    #or
    ό,τι                 #literal greek phrase
    |                    #or
    <br\s*/>             #html break tag
    |                    #or
    \.{3}                #three literal dots (ellipsis)
  )                      #end non-capturing group #2
  (*SKIP)(*FAIL)         #discard anything matched by group #2
  |                      #or
  ([:,.])                #capture group #1
)                        #end non-capturing group #1
\s*                      #zero or more whitespaces
~                        #ending pattern delimiter

As you wish to extend your pattern to include more disqualifying rules, just add another pipe and add a subpattern to match the unwanted substring.

Code: (Demo)

$text = <<<TEXT
Composition:80% Polyamide,   15% Elastane, 5% Wool.
Side length 50.5 cm <---- THIS SHOULDN'T BE MATCHED
Value 4,500 <---- THIS SHOULDN'T BE MATCHED EITHER

What about $1,234,567.89?

ό,τι<---- THIS IS A FIXED PHRASE IN GREEK AND THEREFORE SHOULDN'T BE MATCHED
Comfort and timeless design characterize the Puma Smash V2 made of suede leather. They can be worn all the time ,being a unique choice for those who want to stand out .Made of rubber.<br />- Softfoam floor<br />- Binding with laces

Specs:<br />&bull; Something<br /><br />&bull; Something else<br />&bull; One more

Children's Form Champion<br /><br />Children's set that will give a comfortable feeling for endless hours of play.<br />It consists of a cardigan and trousers ,made of soft fabric and have rib cuffs and legs for a better fit.<br /><br />&bull; Normal fit<br /><br />&bull; Cardigan  :Rib cuffs, zippers throughout length, high neck, Champion logo <br /> <br />&bull; Pants: Elastic waist with drawstring, ribbed legs, Champion logo. Don't worry,there'll be ...more!
TEXT;

echo preg_replace(
         '~\s*(?:(?:\.\d |\d{1,3}(?:,\d{3}) |ό,τι|<br\s*/>|\.{3})(*SKIP)(*FAIL)|([:,.]))\s*~',
         '$1 ',
         $text
     );

Output:

Composition: 80% Polyamide, 15% Elastane, 5% Wool. Side length 50.5 cm <---- THIS SHOULDN'T BE MATCHED
Value 4,500 <---- THIS SHOULDN'T BE MATCHED EITHER

What about $1,234,567.89?

ό,τι<---- THIS IS A FIXED PHRASE IN GREEK AND THEREFORE SHOULDN'T BE MATCHED
Comfort and timeless design characterize the Puma Smash V2 made of suede leather. They can be worn all the time, being a unique choice for those who want to stand out. Made of rubber. <br />- Softfoam floor<br />- Binding with laces

Specs: <br />&bull; Something<br /><br />&bull; Something else<br />&bull; One more

Children's Form Champion<br /><br />Children's set that will give a comfortable feeling for endless hours of play. <br />It consists of a cardigan and trousers, made of soft fabric and have rib cuffs and legs for a better fit. <br /><br />&bull; Normal fit<br /><br />&bull; Cardigan: Rib cuffs, zippers throughout length, high neck, Champion logo <br /> <br />&bull; Pants: Elastic waist with drawstring, ribbed legs, Champion logo. Don't worry, there'll be ...more!