PHP 8.1.0 RC 4 available for testing

str_starts_with

(PHP 8)

str_starts_withChecks if a string starts with a given substring

Descrição

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

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

Parâmetros

haystack

The string to search in.

needle

The substring to search for in the haystack.

Valor Retornado

Returns true if haystack begins with needle, false otherwise.

Exemplos

Exemplo #1 Using the empty string ''

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

O exemplo acima irá imprimir:

All strings start with the empty string

Exemplo #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';
}

?>

O exemplo acima irá imprimir:

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

Notas

Nota: Esta função é binary-safe.

Veja Também

  • str_contains() - Determine if a string contains a given substring
  • str_ends_with() - Checks if a string ends with a given substring
  • stripos() - Encontra a primeira ocorrencia de uma string sem diferenciar maiúsculas e minúsculas
  • strrpos() - Encontra a posição da última ocorrência de um caractere em uma string
  • strripos() - Encontra a posição da última ocorrência de uma string case-insensitive em uma string
  • strstr() - Encontra a primeira ocorrencia de uma string
  • strpbrk() - Procura na string por um dos caracteres de um conjunto
  • substr() - Retorna uma parte de uma string
  • preg_match() - Perform a regular expression match

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User Contributed Notes 2 notes

up
28
Paul Phillips
7 months ago
You can use this in PHP versions less than 8.

<?php
function str_starts_with ( $haystack, $needle ) {
  return
strpos( $haystack , $needle ) === 0;
}
up
6
jgusta
7 months 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.
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