Quickly change translatable strings using gettext filter - WordPress

To translate or change text within a WordPress theme / plugin, we want to edit the theme / plugin PO file ( if the theme has been localized ).

Consider that we have to quickly change a few words on our site though without editing the PO file. We can easily do this by using a WordPress function and gettext filter that will translate / replace any text that has been localized.

Example:

In WooCommerce single product template files, we have a statement like below on related.php file.

<?php _e( 'Related Products', 'woocommerce' ); ?>

We can easily translate these strings by adding a filter to our theme’s functions.php file.

/*
 * Change text strings
 */
function my_text_strings( $translated_text, $text, $domain ) {
	switch ( $translated_text ) {
		case 'Related Products' :
			$translated_text = __( 'Check out these related products', 'woocommerce' );
			break;
	}
	return $translated_text;
}
add_filter( 'gettext', 'my_text_strings', 20, 3 );

Too simple! We can add as many translations to that filter by adding new case statements.