exchanging values of a variable, by values of an array, but under condition

Question

I have a code that compares the output with the values of the array, and only terminates the operation with words in the array:

First code(just a example

Answer 1

My previous method was incredibly inefficient. I didn't realize how much data you were processing, but if we are upwards of 4000 lines, then efficiency is vital (I think I my brain was stuck thinking about strtr() related processing based on your previous question(s)). This is my new/improved solution which I expect to leave my previous solution in the dust.

Code: (Demo)

$myVar="My sister alannis Is not That blonde, here is a good place. I know Ariane is not MY SISTER!";
echo "$myVar\n";

$myWords=array(
    array("is","é"),
    array("on","no"),
    array("that","aquela"),
    array("sister","irmã"), 
    array("my","minha"),
    array("myth","mito"),
    array("he","ele"),
    array("good","bom"),
    array("ace","perito"),
    array("i","eu")  // notice I must be lowercase
);
$translations=array_combine(array_column($myWords,0),array_column($myWords,1));  // or skip this step and just declare $myWords as key-value pairs

// length sorting is not necessary
// preg_quote() and \Q\E are not used because dealing with words only (no danger of misinterpretation by regex)

$pattern='/\b(?>'.implode('|',array_keys($translations)).')\b/i';  // atomic group is slightly faster (no backtracking)
/* echo $pattern;
   makes: /\b(?>is|on|that|sister|my|myth|he|good|ace)\b/i
   demo: https://regex101.com/r/DXTtDf/1
*/
$translated=preg_replace_callback(
    $pattern,
    function($m)use($translations){  // bring $translations (lookup) array to function
        $encoding='UTF-8';  // default setting
        $key=mb_strtolower($m[0],$encoding);  // standardize keys' case for lookup accessibility
        if(ctype_lower($m[0])){ // treat as all lower
            return $translations[$m[0]];
        }elseif(mb_strlen($m[0],$encoding)>1 && ctype_upper($m[0])){  // treat as all uppercase
            return mb_strtoupper($translations[$key],$encoding);
        }else{  // treat as only first character uppercase
            return mb_strtoupper(mb_substr($translations[$key],0,1,$encoding),$encoding)  // uppercase first
                  .mb_substr($translations[$key],1,mb_strlen($translations[$key],$encoding)-1,$encoding);  // append remaining lowercase
        }
    },
    $myVar);

echo $translated;

Output:

My sister alannis Is not That blonde, here is a good place. I know Ariane is not MY SISTER!
Minha irmã alannis É not Aquela blonde, here é a bom place. Eu know Ariane é not MINHA IRMÃ!

This method:

• does only 1 pass through $myVar, not 1 pass for every subarray of $myWords.
• does not bother with sorting the lookup array ($myWords/$translations).
• does not bother with regex escaping (preg_quote()) or making pattern components literal (\Q..\E) because only words are being translated.
• uses word boundaries so that only complete word matches are replaced.
• uses an atomic group as a micro-optimization which maintains accuracy while denying backtracking.
• declares an $encoding value for stability / maintainability / re-usability.
• matches with case-insensitivity but replaces with case-sensitivity ...if the English match is:
  1. All lowercase, so is the replacement
  2. All uppercase (and larger than a single character), so is the replacement
  3. Capitalized (only first character of multi-character string), so is the replacement