substr_count

    (PHP 4, PHP 5, PHP 7, PHP 8)

    substr_count — Cuenta el número de ocurrencias de segmentos en un string

    Descripción

    substr_count(
        string $haystack,
        string $needle,
        int $offset = 0,
        ?int $length = null
    ): int

    substr_count() devuelve el número de ocurrencias de needle en el string haystack. Tenga en cuenta que needle es sensible a mayúsculas y minúsculas.

    Nota:

    Esta función no cuenta los strings que se solapan. Véase el ejemplo a continuación.

    Parámetros

    haystack

    El string en el que se busca

    needle

    El string que se busca

    offset

    El desplazamiento desde donde se comienza a contar. Si la posición es negativa, el conteo comienza desde el final del string.

    length

    La longitud máxima después del desplazamiento especificado para buscar el string. La función emite un error si el desplazamiento más la longitud es mayor que la longitud de haystack. Una longitud negativa hará que el conteo comience al final de haystack.

    Valores devueltos

    Esta función devuelve un entero.

    Historial de cambios

    Versión Descripción
    8.0.0 length ahora puede ser nullable.
    7.1.0 Se agregó soporte para números negativos para offset y length. length también puede ser 0 ahora.

    Ejemplos

    Ejemplo #1 Ejemplo con substr_count()

    <?php
    $text     = 'Esto es una prueba';
    echo     strlen($text), PHP_EOL; // 16

    echo substr_count($text, 'es'), PHP_EOL; // 2

    // el string se reduce a 'st una prueba', por lo que muestra 1
    echo substr_count($text, 'es', 6), PHP_EOL;

    // el texto se reduce a 'st u', por lo que muestra 0
    echo substr_count($text, 'is', 3, 3), PHP_EOL;

    // muestra solo 1, porque no cuenta los strings
    // que se solapan
    $text2 = 'gcdgcdgcd';
    echo     substr_count($text2, 'gcdgcd'), PHP_EOL;

    // lanza una excepción porque 5+10 > 14
    echo substr_count($text, 'is', 5, 10), PHP_EOL;
    ?>

    Ver también

    • count_chars() - Devuelve estadísticas sobre los caracteres utilizados en un string
    • strpos() - Busca la posición de la primera ocurrencia en un string
    • substr() - Devuelve un segmento de string
    • strstr() - Encuentra la primera ocurrencia en un string

    Found A Problem?

    Learn How To Improve This Page • Submit a Pull Request • Report a Bug
    ＋add a note

    User Contributed Notes 7 notes

    up
    60
    tuxedobob
    9 years ago
    It's worth noting this function is surprisingly fast. I first ran it against a ~500KB string on our web server. It found 6 occurrences of the needle I was looking for in 0.0000 seconds. Yes, it ran faster than microtime() could measure.

    Looking to give it a challenge, I then ran it on a Mac laptop from 2010 against a 120.5MB string. For one test needle, it found 2385 occurrences in 0.0266 seconds. Another test needs found 290 occurrences in 0.114 seconds.

    Long story short, if you're wondering whether this function is slowing down your script, the answer is probably not.
    up
    11
    flobi at flobi dot com
    18 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
    2
    tweston at bangordailynews dot com
    10 years ago
    To account for the case that jrhodes has pointed out, we can change the line to:

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

    This way:

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

    Becomes

    mystringth,atislong

    Which brings the count for $needle = "that" to 0 again.
    up
    -1
    jrhodes at roket-enterprises dot com
    16 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
    -1
    info at fat-fish dot co dot il
    18 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
    -1
    XinfoX X at X XkarlX X-X XphilippX X dot X XdeX
    21 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
    -4
    php at blink dot at
    11 years 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>";
    }
    ＋add a note
    To Top