str_replace仅匹配

Question

Good Day,

I am trying to create a morse code to text and text to morse code converter.

My code:

$letter = str_split(strtolower($_POST['text']));
$morse = $_POST['morse'];
$morsecmp = explode(" ",$morse);
$letter = implode(" ",$letter);
$mode = $_POST['sub'];

$morsecode = array(".-","-...","-.-.","-..","..-.","--.","....","..",".---","-.-",".-..","--","-.","---",
            ".--.","--.-",".-.","...","-.","..-","...-",".--","-..-","-.--","--..",".");
$letters = array("a","b","c","d","f","g","h","i","j","k","l","m","n","o","p","q","r",
            "s","t","u","v","w","x","y","z","e");

if($mode == "Text to Morse Code"){  
    $letter = str_replace($letters,$morsecode,$letter);
    $translated = $letter;
}else{
    for($x=0;$x<sizeof($letters);$x++){
        for($y=0;$y<sizeof($morsecmp);$y++){

            if($morsecode[$x] === $morsecmp[$y]){
                echo $morsecode[$x]." === ".$letters[$x]."<br>";
                $morse = str_replace($morsecode[$x],$letters[$x],$morse);
            }
        }
    }
    $translated = $morse;
}

sample input:

.... . .-.. .-.. --- .-- --- .-. .-.. -..

sample output:

h e ed ed o w o r ed d

expected output:

hello wolrd

My problem is that when converting from morse code to text some characters are not captured properly due to str_replace limit where it will replace all string that is similar to the needle, so if i have to replace all "." to e it will also change "...." which should be actually an h.

any help on this would be greatly appreciated.

Thank You.

Answer 1

Just when you repalce the characters add an extra space for the search string.

 $morse = $_POST['morse']." ";  // this is to add an extra space at the end of the morse string.

Now we replace all occurrences of morse code strings followed by space with the desired letter.

 $morse = str_replace($morsecode[$x]." ",$letters[$x],$morse);