I'm trying to validate my input in PHP, how to check if @username exists in the string in the following valid formats in UTF8?
Valid:
Invalid
The following code works, but claims "@usernamehow" is valid when searching for "@username"
$userMentioned = substr_count($text, $username);
To match the specific patterns you mention, you could use a simple Regular Expression with a one-sided word boundary:
$pattern = '/@username\b/';
$userMentioned = preg_match($pattern, $testString);
That will ensure there is no other letters or numbers on the right side, but allows for it on the left side.
\b may be wrong here because it will match @username+xyz which may not be what OP wants
I think you're basically asking how to check if a word is present within a string with PHP. This could be done by using REGEX as rock321987 suggested, or by using strpos():
$word = " @username ";
$string = "Hello @username how are you?";
if (strpos($string, $word) !== false) {
die('Found it');
}
I found out that Laravel is using the exact same approach:
/**
* Determine if a given string contains a given substring.
*
* @param string $haystack
* @param string|array $needles
* @return bool
*/
function str_contains($haystack, $needles)
{
foreach ((array) $needles as $needle)
{
if ($needle != '' && strpos($haystack, $needle) !== false) return true;
}
return false;
}
Hope this helps.
preg_match("/@username(?=\\s|$)/", $username)