How to check a string contains substring in php?

The function will check a string contains substring, the string to be checked may contain underscores.

1. Code:

2. Example:

Input:

$str = "Soltuts.com is providing PHP tutorials";
$substr = "Soltuts.com";
$substr1 = "PHP_tutorials";
checkContainsSubstringWithUnderscore($str, $substr);
checkContainsSubstringWithUnderscore($str, $substr1);

Output:

bool(true)  
bool(true)