the problem is there isnt any HTML tags to identify them. theyre flat text. so theres nothing to know where they are. we can find http, or www. but theres nothing to say where the end of the url ends.
in the above text, we can identify the start of the URL, but the query wont be able to identify where it ends, unless we can give it a specific set of characters to look for.
i can tell it to look for "xyz" and swap it with "123", but because all the URL's are different, we cant specify all the variables that it "could be".