Question

I am trying to parse a string. The catch is each of the variables in the string may occur more than once, and I need to replace each repeated occurrence with a unique replacement.

example $string = "$Pronoun $Adjective $Noun is as $Adjective as an $Adjective $Noun"

I’ve tried str_replace("$Pronoun", getRandomWordByType('Pronoun'), $string)

This works apart from the fact that each occurrence of “$Pronoun” gets replaced with the same pronoun retrieved from a single call to my getRandomWordByType('Pronoun') method.

My objective is to build interesting sentences dynamically, replacing placeholders with words retrieved from a database of words, that are categorised by type…

Thanks in advance for any suggestions 🙂

Answer 1

Try this:

preg_replace_callback("(\$([a-z]+))i",function($a) {return getRandomWordByType($a[1]);},$string);

This will automatically convert any keyword of the form $Something by passing Something to the getRandomWordByType function. Another advantage is that the random word function is called once for each word.

To prevent accidental replacements, for example $NotAKeyword, have getRandomWordByType return '$'.$keyword (where $keyword is the function’s argument) if it can’t find the keyword in the valid list.