<?php
if (is_string("23")) {
echo "is string\n";
} else {
echo "is not an string\n";
}
var_dump(is_string('abc'));
var_dump(is_string("23"));
var_dump(is_string(23.5));
var_dump(is_string(true));
?>
The above example will output:
is string
bool(true)
bool(true)
bool(false)
bool(false)