php check if string contains a char

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

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

1if (strpos($haystack,$needle) !== false) {
2    echo "$haystack contains $needle";
3}

1$haystack = 'This is my haystack that we shall check'
2$has_A = strpos($haystack, 'A') !== false;
3$has_a = strpos($haystack, 'a') !== false;
4

1// returns true if $needle is a substring of $haystack
2function contains($haystack, $needle){
3    return strpos($haystack, $needle) !== false;
4}