如何根据字母变体数组获取所有类似的字符串

Question

I keep trying to wrap my brain around this but I am effectively trying to generate an array/list of all variations of a given string based on an array of letter variations.

I have the string "fabien", and I have an array of variations for each letter involved. For instance A is replaceable with 4, i is replaceable with 1 and l. So given the information how can I generate a list of every variation of "fabien".

$variants = array();
$variants['a'] = array('4');
$variants['i'] = array('1', 'l');

$string = 'fabien';

$result = getVariants('fabien', $variants);

print_r($results);

// Sample output:
Array ([0] => fabien [1] => f4bien [2] => fab1en [3] => fablen [4] => f4b1en [5] => f4blen)

Answer 1

Your case can be easily implemented with recursion. That will be like:

function getVariants($string, $variants)
{
    //here's about stripping 1 symbol from string's right, so 
    //may be you'll prefer to work with string functions:
    $string  = is_array($string)?$string:str_split($string);
    $symbol  = array_pop($string);
    $variant = array_key_exists($symbol, $variants)?
               array_merge([$symbol], $variants[$symbol]):
               [$symbol];
    $result  = [];
    if(!count($string))
    {
        return $variant;
    }
    foreach(getVariants($string, $variants) as $piece)
    {
        foreach($variant as $char)
        {
            $result[] = $piece.$char;
        }
    }
    return $result;
}

-see fiddle demo. How is this working? The answer is: variation of string with length N is variations of it's right symbol 'multiplied' on variations of it's part without that symbol (i.e. with length N-1). By 'multiplication' I mean Decart product of two sets and then concatenation of two parts, that are in certain pair.