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    preg_grep

    (PHP 4, PHP 5, PHP 7)

    preg_grep — Retourne un tableau avec les résultats de la recherche

    Description

    array preg_grep ( string $pattern , array $input [, int $flags = 0 ] )

    preg_grep() retourne un tableau qui contient les éléments de input qui satisfont le masque pattern.

    Liste de paramètres

    pattern

    Le motif à chercher, sous la forme d'une chaîne de caractères.

    input

    Le tableau d'entrée.

    flags

    Si cette option vaut PREG_GREP_INVERT, cette fonction retourne les éléments du tableau input qui ne correspondent pas au motif pattern.

    Valeurs de retour

    Retourne un tableau indexé, en utilisant les clés du tableau input d'entrée.

    Exemples

    Exemple #1 Exemple avec preg_grep()

    <?php
    // Recherche les nombres à virgule flottante dans le tableau
    $fl_array = preg_grep("/^(\d+)?\.\d+$/", $array);
    ?>

    Voir aussi

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    User Contributed Notes 6 notes

    up
    51
    Daniel Klein
    5 years ago
    A shorter way to run a match on the array's keys rather than the values:

    <?php
    function preg_grep_keys($pattern, $input, $flags = 0) {
        return     array_intersect_key($input, array_flip(preg_grep($pattern, array_keys($input), $flags)));
    }
    ?>
    up
    2
    amolocaleb at gmail dot com
    3 months ago
    This may be obvious to most experienced developers,but just in case its not,when using preg_grep to check for whitelisted items ,one must be very careful to explicitly define the regex boundaries or it will fail
    <?php
    $whitelist     = ["home","dashboard","profile","group"];
    $possibleUserInputs = ["homd","hom","ashboard","settings","group"];
    foreach(    $possibleUserInputs as  $input)
    {
         if(    preg_grep("/$input/i",$whitelist)
        {
             echo     $input." whitelisted";
        }else{
             echo     $input." flawed";
        }

    }
    ?>
    This results in:

    homd flawed
    hom whitelisted
    ashboard whitelisted
    settings flawed
    group whitelisted

    I think this is because if boundaries are not explicitly defined,preg_grep looks for any instance of  the substring in the whole array and returns true if found.This is not what we want,so boundaries must be defined.

    <?php
    foreach($possibleUserInputs as  $input)
    {
         if(    preg_grep("/^$input$/i",$whitelist)
        {
             echo     $input." whitelisted";
        }else{
             echo     $input." flawed";
        }

    }
    ?>
    this results in:
    homd flawed
    hom flawed
    ashboard flawed
    settings flawed
    group whitelisted
    in_array() will also give the latter results but will require few tweaks if say,the search is to be case insensitive,which is always the case 70% of the time
    up
    27
    keithbluhm at gmail dot com
    8 years ago
    Run a match on the array's keys rather than the values:

    <?php

    function preg_grep_keys( $pattern, $input, $flags = 0 )
    {
            $keys = preg_grep( $pattern, array_keys( $input ), $flags );
            $vals = array();
        foreach (     $keys as $key )
        {
                $vals[$key] = $input[$key];
        }
        return     $vals;
    }

    ?>
    up
    -1
    Anonymous
    3 months ago
    - Add `filterKeys()`, because now only `filter()` (by values) exists.
    - Add `anchored()` method (or other way) to use anchored patterns.
    - Add a way to replace multiple strings with multiple replacements with one call to `preg_replace()`.
    - Except from `filter()`/`filterKeys()`, add `except()`/`exceptKeys()` to filter out entries that match.
    up
    -13
    Timo Klemm
    1 year ago
    An even shorter way to run a match on the array's keys rather than the values:

    <?php
    function preg_grep_keys($pattern, $input, $flags = 0) {
        return     array_flip( preg_grep($pattern, array_flip($input), $flags ) );
    }
    ?>
    up
    -108
    vickyssj7 at gmail dot com
    4 years ago
    A very simple example to match multiple "."(dot) in an array value:-

    <?php

         $array     = array("23.32","22","12.009","23.43.43");
             print_r(preg_grep("/^(\d+)?\.\d+\.\d+$/",$array));

    ?>
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