PHP Australia Conference 2015

substr_count

(PHP 4, PHP 5)

substr_countCompte le nombre d'occurrences de segments dans une chaîne

Description

int substr_count ( string $haystack , string $needle [, int $offset = 0 [, int $length ]] )

substr_count() retourne le nombre d'occurrences de needle dans la chaîne haystack. Notez que needle est sensible à la casse.

Note:

Cette fonction ne compte pas les chaînes de caractères qui se recouvrent. Voyez l'exemple ci-dessous !

Liste de paramètres

haystack

La chaîne de caractères pour rechercher à l'intérieur

needle

La chaîne de caractères que l'on recherche

offset

Le décalage où on commence à compter

length

La taille maximale après le décalage spécifié pour rechercher la chaîne. La fonction émet une erreur si le décalage plus la taille est plus grand que la taille de haystack.

Valeurs de retour

Cette fonction retourne un entier.

Historique

Version Description
5.1.0 Ajout des paramètres offset et length

Exemples

Exemple #1 Exemple avec substr_count()

<?php
$text 
'Ceci est un test';
echo 
strlen($text); // 16

echo substr_count($text'est'); // 2

// la chaîne de caractères est réduite à 'st un test', alors elle affiche 1
echo substr_count($text'est'6);

// le texte est réduit à 'st u', alors elle affiche 0
echo substr_count($text'est'64);

// génère une erreur parce que 8+10 > 16
echo substr_count($text'est'810);


// affiche seulement 1, parce que elle ne compte pas les chaînes de caractères
// qui se recouvrent
$text2 'gcdgcdgcd';
echo 
substr_count($text2'gcdgcd');
?>

Voir aussi

  • count_chars() - Retourne des statistiques sur les caractères utilisés dans une chaîne
  • strpos() - Cherche la position de la première occurrence dans une chaîne
  • substr() - Retourne un segment de chaîne
  • strstr() - Trouve la première occurrence dans une chaîne

add a note add a note

User Contributed Notes 8 notes

up
6
jrhodes at roket-enterprises dot com
5 years ago
It was suggested to use

substr_count ( implode( $haystackArray ), $needle );

instead of the function described previously, however this has one flaw.  For example this array:

array (
  0 => "mystringth",
  1 => "atislong"
);

If you are counting "that", the implode version will return 1, but the function previously described will return 0.
up
5
info at fat-fish dot co dot il
7 years ago
a simple version for an array needle (multiply sub-strings):
<?php

function substr_count_array( $haystack, $needle ) {
    
$count = 0;
     foreach (
$needle as $substring) {
         
$count += substr_count( $haystack, $substring);
     }
     return
$count;
}
?>
up
2
gigi at phpmycoder dot com
5 years ago
below was suggested a function for substr_count'ing an array, yet for a simpler procedure, use the following:

<?php
substr_count
( implode( $haystackArray ), $needle );
?>
up
1
flobi at flobi dot com
7 years ago
Making this case insensitive is easy for anyone who needs this.  Simply convert the haystack and the needle to the same case (upper or lower).

substr_count(strtoupper($haystack), strtoupper($needle))
up
1
XinfoX X at X XkarlX X-X XphilippX X dot X XdeX
10 years ago
Yet another reference to the "cgcgcgcgcgcgc" example posted by "chris at pecoraro dot net":

Your request can be fulfilled with the Perl compatible regular expressions and their lookahead and lookbehind features.

The example

$number_of_full_pattern = preg_match_all('/(cgc)/', "cgcgcgcgcgcgcg", $chunks);

works like the substr_count function. The variable $number_of_full_pattern has the value 3, because the default behavior of Perl compatible regular expressions is to consume the characters of the string subject that were matched by the (sub)pattern. That is, the pointer will be moved to the end of the matched substring.
But we can use the lookahead feature that disables the moving of the pointer:

$number_of_full_pattern = preg_match_all('/(cg(?=c))/', "cgcgcgcgcgcgcg", $chunks);

In this case the variable $number_of_full_pattern has the value 6.
Firstly a string "cg" will be matched and the pointer will be moved to the end of this string. Then the regular expression looks ahead whether a 'c' can be matched. Despite of the occurence of the character 'c' the pointer is not moved.
up
0
php at blink dot at
2 months ago
This will handle a string where it is unknown if comma or period are used as thousand or decimal separator. Only exception where this leads to a conflict is when there is only a single comma or period and 3 possible decimals (123.456 or 123,456). An optional parameter is passed to handle this case (assume thousands, assume decimal, decimal when period, decimal when comma). It assumes an input string in any of the formats listed below.

function toFloat($pString, $seperatorOnConflict="f")
{
    $decSeperator=".";
    $thSeperator="";

    $pString=str_replace(" ", $thSeperator, $pString);

    $firstPeriod=strpos($pString, ".");
    $firstComma=strpos($pString, ",");
    if($firstPeriod!==FALSE && $firstComma!==FALSE) {
        if($firstPeriod<$firstComma) {
            $pString=str_replace(".", $thSeperator, $pString);
            $pString=str_replace(",", $decSeperator, $pString);
        }
        else {
            $pString=str_replace(",", $thSeperator, $pString);
        }
    }
    else if($firstPeriod!==FALSE || $firstComma!==FALSE) {
        $seperator=$firstPeriod!==FALSE?".":",";
        if(substr_count($pString, $seperator)==1) {
            $lastPeriodOrComma=strpos($pString, $seperator);
            if($lastPeriodOrComma==(strlen($pString)-4) && ($seperatorOnConflict!=$seperator && $seperatorOnConflict!="f")) {
                $pString=str_replace($seperator, $thSeperator, $pString);
            }
            else {
                $pString=str_replace($seperator, $decSeperator, $pString);
            }
        }
        else {
            $pString=str_replace($seperator, $thSeperator, $pString);
        }
    }
    return(float)$pString;
}

function testFloatParsing() {
    $floatvals = array(
        "22 000",
        "22,000",
        "22.000",
        "123 456",
        "123,456",
        "123.456",
        "22 000,76",
        "22.000,76",
        "22,000.76",
        "22000.76",
        "22000,76",
        "1.022.000,76",
        "1,022,000.76",
        "1,000,000",
        "1.000.000",
        "1022000.76",
        "1022000,76",
        "1022000",
        "0.76",
        "0,76",
        "0.00",
        "0,00",
        "1.00",
        "1,00",
        "-22 000,76",
        "-22.000,76",
        "-22,000.76",
        "-22 000",
        "-22,000",
        "-22.000",
        "-22000.76",
        "-22000,76",
        "-1.022.000,76",
        "-1,022,000.76",
        "-1,000,000",
        "-1.000.000",
        "-1022000.76",
        "-1022000,76",
        "-1022000",
        "-0.76",
        "-0,76",
        "-0.00",
        "-0,00",
        "-1.00",
        "-1,00"
    );
   
    echo "<table>
        <tr>
            <th>String</th>
            <th>thousands</th>
            <th>fraction</th>
            <th>dec. if period</th>
            <th>dec. if comma</th>
        </tr>";
       
    foreach ($floatvals as $fval) {
        echo "<tr>";
        echo "<td>" . (string) $fval . "</td>";
       
        echo "<td>" . (float) toFloat($fval, "") . "</td>";
        echo "<td>" . (float) toFloat($fval, "f") . "</td>";
        echo "<td>" . (float) toFloat($fval, ".") . "</td>";
        echo "<td>" . (float) toFloat($fval, ",") . "</td>";
        echo "</tr>";
    }
    echo "</table>";
}
up
-2
qeremy [atta] gmail [dotta] com
1 year ago
Unicode example with "case-sensitive" option;

<?php
function substr_count_unicode($str, $substr, $caseSensitive = true, $offset = 0, $length = null) {
    if (
$offset) {
       
$str = substr_unicode($str, $offset, $length);
    }

   
$pattern = $caseSensitive
       
? '~(?:'. preg_quote($substr) .')~u'
       
: '~(?:'. preg_quote($substr) .')~ui';
   
preg_match_all($pattern, $str, $matches);

    return isset(
$matches[0]) ? count($matches[0]) : 0;
}

function
substr_unicode($str, $start, $length = null) {
    return
join('', array_slice(
       
preg_split('~~u', $str, -1, PREG_SPLIT_NO_EMPTY), $start, $length));
}

$s = 'Ümit yüzüm gözüm...';
print
substr_count_unicode($s, 'ü');            // 3
print substr_count_unicode($s, 'ü', false);     // 4
print substr_count_unicode($s, 'ü', false, 10); // 1

print substr_count_unicode($s, 'üm');           // 2
print substr_count_unicode($s, 'üm', false);    // 3
?>
up
-5
chrisstocktonaz at gmail dot com
5 years ago
In regards to anyone thinking of using code contributed by zmindster at gmail dot com

Please take careful consideration of possible edge cases with that regex, in example:

$url = 'http://w3.host.tld/path/to/file/..../file.extension';
$url = 'http://w3.host.tld/path/to/file/../file.extension?malicous=....';

This would cause a infinite loop and for example be a possible entry point for a denial of service attack. A correct fix would require additional code, a quick hack would be just adding a additional check, without clarity or performance in mind:

...
$i = 0;
while (substr_count($url, '../') && ++$i < strlen($url))
...

-Chris
To Top