If I understand you well, I think you need to find a string like {fl or az} in the current URL and this can be done by exploding the current URL into pieces.
If you confused about the code, we assigned and checked variables like {$url_path and $url_parts} inside if statement
/*
* NOTES:
*
* get_site_url() function return the
* current site url without trailing slash
* like { **http://www.example.com/fl** }
*
* FUN: parse_url: with const {PHP_URL_PATH} return the URL path after {.com}
*
* FUN: explode: separate words by delimiter "https://wordpress.stackexchange.com/" and {@} to avoid errors
*
* because of parse_url return the path after {.com} so the string
* {$url_path} starts with {/fl} so you we used the key number {1} not {0}
*
*/
$site_url = get_site_url();
if( ! empty( $url_path = parse_url( $site_url, PHP_URL_PATH ) ) ) {
if( is_array( $url_parts = @explode( "https://wordpress.stackexchange.com/", $url_path ) ) &&
( count( $url_parts ) > 0 ) &&
array_key_exists( 1, $url_parts ) ) {
switch( $url_parts[1] ) {
case 'fl': {
/* === DO === */
} break;
case 'az': {
/* === DO === */
} break;
}
}
}