check if string contains character php

1$myString = 'Hello Bob how are you?';
2if (strpos($myString, 'Bob') !== false) {
3    echo "My string contains Bob";
4}

1$a = 'How are you?';
2
3if (strpos($a, 'are') !== false) {
4    echo 'true';
5}
6

1if (strpos($string, 'substring') !== false) {
2	// do stuff 
3}

1$a = 'Hello world?';
2
3if (strpos($a, 'Hello') !== false) { //PAY ATTENTION TO !==, not !=
4    echo 'true';
5}
6if (stripos($a, 'HELLO') !== false) { //Case insensitive
7    echo 'true';
8}

1$result = strpos("haystack", "needle");
2
3if ($result != false)
4{
5  // text found
6}

1// this method is new with PHP 8 and above
2$haystack = "Damn, I wonder if this string contains a comma.";
3if (str_contains($haystack, ",")) {
4	echo "There is a comma!!";
5}