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str_contains

(PHP 8)

str_contains指定された部分文字列が、文字列に含まれるかを調べる

説明

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

needlehaystack に含まれるかを調べます。 大文字小文字は区別されます。

パラメータ

haystack

検索対象の文字列

needle

haystack で調べる部分文字列

戻り値

haystackneedle が含まれていた場合 true そうでない場合、false を返します。

例1 空文字列 '' を使った場合

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

上の例の出力は以下となります。

Checking the existence of the empty string will always return true

例2 大文字小文字の区別

<?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';
}

?>

上の例の出力は以下となります。

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

注意

注意: この関数はバイナリデータに対応しています。

参考

  • str_ends_with() - 文字列が、指定された文字列で終わるかを調べる。
  • str_starts_with() - 文字列が指定された部分文字列で始まるかを調べる
  • stripos() - 大文字小文字を区別せずに文字列が最初に現れる位置を探す
  • strrpos() - 文字列中に、ある部分文字列が最後に現れる場所を探す
  • strripos() - 文字列中で、特定の(大文字小文字を区別しない)文字列が最後に現れた位置を探す
  • strstr() - 文字列が最初に現れる位置を見つける
  • strpbrk() - 文字列の中から任意の文字を探す
  • substr() - 文字列の一部分を返す
  • preg_match() - 正規表現によるマッチングを行う

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User Contributed Notes 9 notes

up
105
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;
}
}
?>
up
13
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 ?: ""`;
up
2
Ancyker
9 months 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, ド 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.
up
4
harl at gmail dot com
10 months 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.)
up
3
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
up
2
juliyvchirkov at gmail dot com
2 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;
}
}
up
-1
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);
}
up
-11
AuxData
2 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
up
-52
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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