Capture and edit part of string using regex in PHP

Question

I have to check several strings...the format of each string could be the following:

I-IVWM_Ask-21_(max_2h)

or

D-7849_DG303_(max_4h)

or

Aliante_Privato

I need to capture text in brackets, first part of string outside brackets and replace underscore with spaces.

I'm tring to use preg_match in PHP, as follow

preg_replace('/\([^)]*\)|[()]/', '', $string);

The code above remove string and brackets but leave underscore and doesn't capture the string inside brackets.

Any help to figure out my issue? Thanks

The fourth bird · Accepted Answer · 2021-08-04 08:11:41Z

2

What you might do is first match the pattern, and for the match replace the parenthesis and underscores with a space using preg_replace_callback.

Pattern to match the strings:

^[^\s()]+(?:\([^()]*\))?$

^ Start of string
[^\s()]+ Match 1+ chars other than parenthesis or whitespace chars
(?:$[^()]*$)? Optionally match the part between parenthesis
$ End of string

Regex demo | Php demo

For example

$strings = [
    "I-IVWM_Ask-21_(max_2h)",
    "D-7849_DG303_(max_4h)",
    "Aliante_Privato"
];

foreach ($strings as $str) {
    $pattern = "/^[^\s()]+(?:\([^()]*\))?$/";
    echo preg_replace_callback($pattern, function ($x) {
        return trim(preg_replace("/[()_]+/", " ", $x[0]));
    }, $str) . PHP_EOL;
}

Output

I-IVWM Ask-21 max 2h
D-7849 DG303 max 4h
Aliante Privato

answered Aug 4, 2021 at 8:11

The fourth bird

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3 Comments

Federico Over a year ago

Thanks a lot for your help. I'm trying to understand the pattern but it's very criptic to me....is there a way to get back the string splitted in three groups? The first should be the code with a letter, minus sign and four numbers/letters ( D-7849 or I-IVWM, the second shold be the model name ( Ask-21 .. for example ), the last group should be the duration ( max 2h ) Thanks a lot again...still needs to learn a lot about regex...

The fourth bird Over a year ago

@Federico Like this? ^([A-Z]-[A-Z0-9]{4})_([A-Za-z0-9]+(?:-[A-Za-z0-9]+)*)_$([^()]+)$ regex101.com/r/AkPfD6/1 Then you can replace the underscore from the 3rd group using preg_replace_callback as in the example.

Federico Over a year ago

Unbelieveble!...the power of regex is incredible. Thanks a lot again for invaluable help!

Casimir et Hippolyte · Accepted Answer · 2021-08-10 20:07:36Z

2

$strings = [
    "I-IVWM_Ask-21_(max_2h)",
    "D-7849_DG303_(max_4h)",
    "Aliante_Privato"
];

$result = array_map('trim', preg_filter('~[_()]+~', ' ', $strings));

answered Aug 10, 2021 at 20:07

Casimir et Hippolyte

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3 Comments

Federico Over a year ago

Really interesting Casimir…can I ask what’s the purpose of the square bracket? Needs to understand array_map function too

Casimir et Hippolyte Over a year ago

@Federico: square brackets are not different than something like [A-Z], they defines a character class, except that this one doesn't contain a range of letters but only 3 characters (, ), _. array_map applies a function to each item of an array and returns a new array. The applied function is simply trim. Note that this answer has nothing special and the code doesn't check the format, but I wrote it only to show a certain conciseness to treat an array "in one shot". Following the same idea, you can use preg_grep to select items that match the desired format.

Federico Over a year ago

Great feedback and support...as usual. Thanks a lot

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