Better solution than nested if-else?

Not sure how this describe this with a better title, however here is my problem:

i have a replace function with multiple boolean options:

1. regex
2. whole words (only when regex==false)
3. case sensitive

and this means i have to choose 1 of 4 ways to replace my text. Currently my code loo开发者_如何学Pythonks like this:

(those options here are indeed true/false as a string, passed in via POST from a set of jquery checkboxes)

    if($regex=='true')
    {
        if($casesens=='true')
        {
            $p->aData['body'] = preg_replace('/'.$q.'/', $r, $p->aData['body']);
        }
        else
        {
            $p->aData['body'] = preg_replace('/'.$q.'/i', $r, $p->aData['body']);           
        }
    }
    else
    {
        if($wwords=='true')
        {
            $q = " ".$q." ";
            $r = " ".$r." ";
        }
        if($casesens=='true')
        {
            $p->aData['body'] = str_replace($q, $r, $p->aData['body']);
        }
        else
        {
            $p->aData['body'] = str_ireplace($q, $r, $p->aData['body']);
        }
    }

as you can see, if have to compare $casesens in both conditons, and this becomes increasingly complex if i have to add more options to the UI. Is there a better or more elegant way to write this?

Well you can certainly simplify what you have by cutting down a lot of unnecessary duplication, something like:

if(!$regex) $q = preg_quote($q);
elseif($words) $q = "\s{$q}\s/";
$q = "/{$q}/";
if($casesens) $q .= 'i';
$p->aData['body'] = preg_replace($q, $r, $p->aData['body']);

I wouldn't call that elegant, but at least it's shorter.

You could simply do the check for $casesens once and define a variable like this:

if($casesens=='true') {
    $case = 'i';
}

And then use it in the regex pattern just like any other variable:

$p->aData['body'] = preg_replace('/'.$q.'/'.$case, $r, $p->aData['body']);

This would solve the first if. As for the second one I can think of 2 ways:

1. Create a function similar to str_replace and stri_replace that takes an extra boolean argument, to ignore case or not and, call the appropriate string replace function.
2. You could use preg_replace instead of the string replace functions just like you previously did and use the same way to solve the problem as I explained above.

You can use the PHP Ternary Operators to reduce the complexity

http://davidwalsh.name/php-shorthand-if-else-ternary-operators