私が持っているとしましょう:
$strPar = "This is a simple paragraph that we will use for the questioning";
$strFindMe = "that";
$strParが含まれているかどうかを確認するにはどうすればよい$strFindMeですか?
$string = "This is a strpos() test";
$pos = strpos($string, "i", 3);
    if ($pos === false) {
     print "Not found\n";
}else{
     print "Found at $pos!\n";
}
    strpos()関数で確認してください。大文字と小文字が区別されます。
if( strpos($strPar, $strFindMe) ) {  //it return a boolean value
   echo "String Found";
}
    <?php
$strPar = "This is a simple paragraph that we will use for the questioning";
$strFindMe   = "that";
$pos = strpos($strPar, $strFindMe);
// Note our use of ===.  Simply == would not work as expected
// because the position of 'a' was the 0th (first) character.
if ($pos === false) {
    echo "The string '$findme' was not found in the string '$mystring'";
} else {
    echo "The string '$findme' was found in the string '$mystring'";
    echo " and exists at position $pos";
}
?>
    $strPar = "This is a simple paragraph that we will use for the questioning";
$strFindMe = "THAT";//Find the position of the first occurrence of a case-insensitive substring in a string
$exists = strpos($strPar, $strFindMe);
  if ($exists !== false) {
    // substring is in the main string
  }