WordPress at a glance
function is not described

WC_Tax::get_rate_code() public WC 1.0

Get a rates code. Code is made up of COUNTRY-STATE-NAME-Priority. E.g GB-VAT-1, US-AL-TAX-1.

{} It's a method of the class: WC_Tax{}

Hooks from the method
Return

String. Nothing.

Usage

$result = WC_Tax::get_rate_code( $key_or_rate );
$key_or_rate(mixed) (required)
Tax rate ID, or the db row itself in object format.

Code of WC_Tax::get_rate_code() WC 5.3.0

<?php
public static function get_rate_code( $key_or_rate ) {
	global $wpdb;

	if ( is_object( $key_or_rate ) ) {
		$key  = $key_or_rate->tax_rate_id;
		$rate = $key_or_rate;
	} else {
		$key  = $key_or_rate;
		$rate = $wpdb->get_row( $wpdb->prepare( "SELECT tax_rate_country, tax_rate_state, tax_rate_name, tax_rate_priority FROM {$wpdb->prefix}woocommerce_tax_rates WHERE tax_rate_id = %s", $key ) );
	}

	$code_string = '';

	if ( null !== $rate ) {
		$code        = array();
		$code[]      = $rate->tax_rate_country;
		$code[]      = $rate->tax_rate_state;
		$code[]      = $rate->tax_rate_name ? $rate->tax_rate_name : 'TAX';
		$code[]      = absint( $rate->tax_rate_priority );
		$code_string = strtoupper( implode( '-', array_filter( $code ) ) );
	}

	return apply_filters( 'woocommerce_rate_code', $code_string, $key );
}