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    str_starts_with

    (PHP 8)

    str_starts_with — Checks if a string starts with a given substring

    Descripción

    str_starts_with(string $haystack, string $needle): bool

    Performs a case-sensitive check indicating if haystack begins with needle.

    Parámetros

    haystack

    The string to search in.

    needle

    The substring to search for in the haystack.

    Valores devueltos

    Returns true if haystack begins with needle, false otherwise.

    Ejemplos

    Ejemplo #1 Using the empty string ''

    <?php
    if (str_starts_with('abc', '')) {
    echo     "All strings start with the empty string";
    }
    ?>

    El resultado del ejemplo sería:

    All strings start with the empty string

    Ejemplo #2 Showing case-sensitivity

    <?php
    $string     = 'The lazy fox jumped over the fence';

    if (    str_starts_with($string, 'The')) {
    echo     "The string starts with 'The'\n";
    }

    if (    str_starts_with($string, 'the')) {
    echo     'The string starts with "the"';
    } else {
    echo     '"the" was not found because the case does not match';
    }

    ?>

    El resultado del ejemplo sería:

    The string starts with 'The'
"the" was not found because the case does not match

    Notas

    Nota: Esta función es segura binariamente.

    Ver también

    • str_contains() - Determine if a string contains a given substring
    • str_ends_with() - Checks if a string ends with a given substring
    • stripos() - Encuentra la posición de la primera aparición de un substring en un string sin considerar mayúsculas ni minúsculas
    • strrpos() - Encuentra la posición de la última aparición de un substring en un string
    • strripos() - Encuentra la posición de la última aparición de un substring insensible a mayúsculas y minúsculas en un string
    • strstr() - Encuentra la primera aparición de un string
    • strpbrk() - Buscar una cadena por cualquiera de los elementos de un conjunto de caracteres
    • substr() - Devuelve parte de una cadena
    • preg_match() - Realiza una comparación con una expresión regular

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    User Contributed Notes 3 notes

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    46
    Paul Phillips
    3 years ago
    You can use this in PHP versions less than 8.

    <?php
    function str_starts_with ( $haystack, $needle ) {
      return     strpos( $haystack , $needle ) === 0;
    }
    up
    13
    jgusta
    3 years ago
    With credit to Paul Phillips for the original polyfill posted.

    If you do not have PHP 8, you can use these functions to get the capability of the new string functions.

    But! Remember to use a conditional check to make sure the function is not already defined.

    <?php
    // source: Laravel Framework
    // https://github.com/laravel/framework/blob/8.x/src/Illuminate/Support/Str.php
    if (!function_exists('str_starts_with')) {
        function     str_starts_with($haystack, $needle) {
            return (string)    $needle !== '' && strncmp($haystack, $needle, strlen($needle)) === 0;
        }
    }
    if (!    function_exists('str_ends_with')) {
        function     str_ends_with($haystack, $needle) {
            return     $needle !== '' && substr($haystack, -strlen($needle)) === (string)$needle;
        }
    }
    if (!    function_exists('str_contains')) {
        function     str_contains($haystack, $needle) {
            return     $needle !== '' && mb_strpos($haystack, $needle) !== false;
        }
    }
    ?>

    This keeps it from breaking in case you upgrade and forget that you added it. This is a good practice generally when using the global scope for your helper functions.
    up
    2
    Reinder
    3 years ago
    In PHP7 you may want to use:

    if (!function_exists('str_starts_with')) {
      function str_starts_with($str, $start) {
        return (@substr_compare($str, $start, 0, strlen($start))==0);
      }
    }

    AFAIK that is binary safe and doesn't need additional checks.
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