(PHP 8)
str_contains — Determine if a string contains a given substring
$haystack, string $needle): bool
Performs a case-sensitive check indicating if needle is contained
in haystack.
haystackThe string to search in.
needle
The substring to search for in the haystack.
Returns true if needle is in
haystack, false otherwise.
Example #1 Using the empty string ''
<?php
if (str_contains('abc', '')) {
echo "Checking the existence of the empty string will always return true";
}
?>
The above example will output:
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($string, 'Lazy')) {
echo 'The string "Lazy" was found in the string';
} else {
echo '"Lazy" was not found because the case does not match';
}
?>
The above example will output:
The string 'lazy' was found in the string "Lazy" was not found because the case does not match
Note: This function is binary-safe.
For earlier versions of PHP, you can polyfill the str_contains function using the following snippet:
<?php
// based on original work from the PHP Laravel framework
if (!function_exists('str_contains')) {
function str_contains($haystack, $needle) {
return $needle !== '' && mb_strpos($haystack, $needle) !== false;
}
}
?>
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 ?: ""`;
<?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;
}
}
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, $filename);
}
The code from "me at daz dot co dot uk" will not work if the word is
- at the start of the string
- at the end of the string
- at the end of a sentence (like "the ox." or "is that an ox?")
- in quotes
- and so on.
You should explode the string by whitespace, punctations, ... and check if the resulting array contains your word OR try to test with a RegEx like this:
(^|[\s\W])+word($|[\s\W])+
Disclaimer: The RegEx may need some tweaks
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
<?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';
}
# Watch out for aberrant partial matches
$string = 'The lazy fox jumped over the fence';
if (str_contains($string, 'ox')) {
echo 'The string "ox" was found in the string because it was a partial match';
} else {
echo '"ox" was not found';
}
//output: The string "ox" was found in the string because it was a partial match
# use spaces for full word matching
$string = 'The lazy fox jumped over the fence';
if (str_contains($string, ' ox ')) {
echo 'The string " ox " was found in the string because it was a partial match';
} else {
echo '" ox " was not found';
}
//output: " ox " was not found
