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str_contains

(PHP 8)

str_contains — Determine if a string contains a given substring

Descrizione

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

Performs a case-sensitive check indicating if needle is contained in haystack.

Elenco dei parametri

haystack: The string to search in.
needle: The substring to search for in the haystack.

Valori restituiti

Returns true if needle is in haystack, false otherwise.

Esempi

Example #1 Using the empty string ''

<?php
if (str_contains('abc', '')) {
    echo "Checking the existence of the empty string will always return true";
}
?>

Il precedente esempio visualizzerà:

Checking the existence of the empty string will always return true

Example #2 Showing case-sensitivity

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

if (str_contains($string, 'lazy')) {
    echo "The string 'lazy' was found in the string\n";
}

if (str_contains($string, 'Lazy')) {
    echo 'The string "Lazy" was found in the string';
} else {
    echo '"Lazy" was not found because the case does not match';
}

?>

Il precedente esempio visualizzerà:

The string 'lazy' was found in the string
"Lazy" was not found because the case does not match

Note

Nota: Questa funzione è binary-safe (gestisce correttamente i file binari)

Vedere anche:

str_ends_with() - Checks if a string ends with a given substring
str_starts_with() - Checks if a string starts with a given substring
stripos() - Trova la prima occorrenza in una stringa senza distinzione tra maiuscole e minuscole
strrpos() - Trova la posizione dell'ultima occorrenza di un carattere in una stringa
strripos() - Trova la posizione dell'ultima occorrenza di una stringa in un'altra indipendentemente dalle lettere minuscole/maiusole
strstr() - Trova la prima occorrenza di una stringa
strpbrk() - Ricerca in una stringa uno qualsiasi dei caratteri di un dato set
substr() - Restituisce parte di una stringa
preg_match() - Riconoscimento con espressioni regolari

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User Contributed Notes 9 notes

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104

scm6079 ¶

3 years ago


For earlier versions of PHP, you can polyfill the str_contains function using the following snippet:

<?php
// based on original work from the PHP Laravel framework
if (!function_exists('str_contains')) {
    function str_contains($haystack, $needle) {
        return $needle !== '' && mb_strpos($haystack, $needle) !== false;
    }
}
?>

down

aisunny7 dot xy at gmail dot com ¶

2 years ago


The polyfill that based on original work from the PHP Laravel framework had a different behavior;

when the $needle is `""` or `null`:
php8's will return `true`;
but, laravel'str_contains will return `false`;

when php8.1, null is deprecated, You can use `$needle ?: ""`;

down

harl at gmail dot com ¶

1 year ago


A couple of functions for checking if a string contains any of the strings in an array, or all of the strings in an array:

<?php
function str_contains_any(string $haystack, array $needles): bool
{
    return array_reduce($needles, fn($a, $n) => $a || str_contains($haystack, $n), false);
}

function str_contains_all(string $haystack, array $needles): bool
{
    return array_reduce($needles, fn($a, $n) => $a && str_contains($haystack, $n), true);
}
?>

str_contains_all() will return true if $needles is an empty array. If you think that's wrong, show me a string in $needles that DOESN'T appear in the $haystack, and then look up "vacuous truth".

(By swapping haystacks and needles in the body of these functions you can create versions that check if a needle appears in any/all of an array of haystacks.)

down

olivertasche+nospam at gmail dot com ¶

3 years ago


The code from "me at daz dot co dot uk" will not work if the word is
- at the start of the string
- at the end of the string
- at the end of a sentence (like "the ox." or "is that an ox?")
- in quotes
- and so on.

You should explode the string by whitespace, punctations, ... and check if the resulting array contains your word OR try to test with a RegEx like this:
(^|[\s\W])+word($|[\s\W])+

Disclaimer: The RegEx may need some tweaks

down

Ancyker ¶

1 year ago


This function doesn't always produce the expected results if you have a needle that isn't UTF-8 but are looking for it in a UTF-8 string. This won't be a concern for most people, but if you are mixing old and new data, especially if reading data from a file, it could be an issue.

Here's a "mb_*"-esque function that searches the string:

<?php
function mb_str_contains(string $haystack, string $needle, $encoding = null) {
    return $needle === '' || mb_substr_count($haystack, $needle, (empty($encoding) ? mb_internal_encoding() : $encoding)) > 0;
}
?>

I used mb_substr_count() instead of mb_strpos() because mb_strpos() will still match partial characters as it's doing a binary search.

We can compare str_contains to the above suggested function:

<?php
// Some Unicode Kanji (漢字はユニコード)
$string = hex2bin('e6bca2e5ad97e381afe383a6e3838be382b3e383bce38389');

// Some Windows-1252 characters (ãƒ)
$contains = hex2bin('e383');
// ^ file_get_contents() produces the same data when it is saved as "ANSI" in Notepad on Windows, so this is not that unrealistic. The only reason to use hex2bin here is to mix character sets without having to use multiple files.

// A character that actually exists in our string. (ー)
$contains2 = hex2bin('e383bc');

echo " = Haystack: ".var_export($string, true)."\r\n";
echo " = Needles:\r\n";
echo "   + Windows-1252 characters\r\n";
echo "     - Results:\r\n";
echo "       >    str_contains: ".var_export(str_contains($string, $contains), true)."\r\n";
echo "       > mb_str_contains: ".var_export(mb_str_contains($string, $contains), true)."\r\n";
echo "   + Valid UTF-8 character\r\n";
echo "     - Results:\r\n";
echo "       >    str_contains: ".var_export(str_contains($string, $contains2), true)."\r\n";
echo "       > mb_str_contains: ".var_export(mb_str_contains($string, $contains2), true)."\r\n";
echo "\r\n";
?>

Output:

 = Haystack: '漢字はユニコード'
 = Needles:
   + Windows-1252 characters
     - Results:
       >    str_contains: true
       > mb_str_contains: false
   + Valid UTF-8 character
     - Results:
       >    str_contains: true
       > mb_str_contains: true

It's not completely foolproof, however. For instance, ãƒ‰ in Windows-1252 will match ド from the above string. So it's still best to convert the encoding of the parameters to be the same first. But, if the character set isn't known/can't be detected and you have no choice but to deal with dirty data, this is probably the simplest solution.

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-1

juliyvchirkov at gmail dot com ¶

3 years ago


<?php

// Polyfill for PHP 4 - PHP 7, safe to utilize with PHP 8

if (!function_exists('str_contains')) {
    function str_contains (string $haystack, string $needle)
    {
        return empty($needle) || strpos($haystack, $needle) !== false;
    }
}

down

-3

drupalista dot com dot br at gmail dot com ¶

2 years ago


private function contains(array $needles, string $type, string $haystack = NULL, string $filename = NULL) : bool {
        if (empty($needles)) return FALSE;
        if ($filename)
            $haystack = file_get_contents($filename);

        $now_what = function(string $needle) use ($haystack, $type) : array {
            $has_needle = str_contains($haystack, $needle);
            if ($type === 'any' && $has_needle)
                return ['done' => TRUE, 'return' => TRUE];

            if ($type === 'all' && !$has_needle)
                return ['done' => TRUE, 'return' => FALSE];

            return ['done' => FALSE];
        };

        foreach ($needles as $needle) {
            $check = $now_what($needle);
            if ($check['done'])
                return $check['return'];
        }
        return TRUE;
    }

    function containsAny(array $needles, string $haystack = NULL, string $filename = NULL) : bool {
        return self::contains($needles, 'any', $haystack, $filename);
    }

    function containsAll(array $needles, string $haystack = NULL, string $filename = NULL) : bool {
        return self::contains($needles, 'all', $haystack, $filename);
    }

down

-13

AuxData ¶

3 years ago


Until PHP 8 was released, many-a-programmer were writing our own contain() functions. Mine also handles needles with logical ORs (set to '||').
Here it is.

function contains($haystack, $needle, $offset){
    $OR = '||';
    $result = false;
    
    $ORpos = strpos($needle, $OR, 0);
    if($ORpos !== false){ //ORs exist in the needle string
        $needle_arr = explode($OR, $needle);
        for($i=0; $i < count($needle_arr); $i++){
            $pos = strpos($haystack, trim($needle_arr[$i]), $offset);
            if($pos !== false){
                $result = true;
                break;
            }
        }        
    } else {
        $pos = strpos($haystack, trim($needle), $offset);
        if($pos !== false){
          $result = true;
        }
    }
  return($result);
}

Call: contains("Apple Orange Banana", "Apple || Walnut", 0);
Returns: true

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-49

kadenskinner at gmail dot com ¶

3 years ago


<?php

$needle = '@';
$haystack = 'user@example.com';

if (!str_contains($haystack, $needle)){
echo 'There is not an @ in haystack';
}else{
echo 'There is an @ in haystack';
}

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