Empty Space in PHP String Explode

Question

Hello, I’m having problems using a EXPLODE in a PHP String. I used a space as delimiter but I need to pick up when there are 3 spaces followed as a position in the Array. It is an exercise of a morse code coder. The word is formed ok but the space between them I cannot place in the output string. If I put another delimiter it would work perfectly, but for the exercise I can’t use another one, and I need to be able to check when it’s just a space or when it’s 3. The code should take morse code and turn it into text...

Thank you very much.

<?php
$morse = [
        ' ' => '   ',
        'A' => '.-', 
        'B' => '-...', 
        'C' => '-.-.', 
        'D' => '-..', 
        'E' => '.', 
        'F' => '..-.', 
        'G' => '--.', 
        'H' => '....', 
        'I' => '..', 
        'J' => '.---' , 
        'K' => '-.-', 
        'L' => '.-..', 
        'M' => '--',
        'N' => '-.', 
        'O' => '---', 
        'P' => '.--.', 
        'Q' => '--.-', 
        'R' => '.-.', 
        'S' => '...', 
        'T' => '-', 
        'U' => '..-',
        'V' => '...-',
        'W' => '.--',
        'X' => '-..-',
        'Y' => '-.--',
        'Z' => '--..'
    ];
    
        $saida = '';
        $mensagem = ".... . -.--   .--- ..- -.. .";

            $letras = explode('', $mensagem);
            foreach($letras as $i => $value)
            {
                $saida .= array_search($letras[$i],$morse);
                
            }
    
            
            echo $saida;
    ?>

Answer 1

On the problem with the spaces, inspect the variable $letras, will realize that it generates two $values "" (empty) for every three spaces. This is because the spaces are being used by split / explode, then it takes everything between the spaces. For three sequent "empty" spaces, between them, the return is "" (emptiness).

Although there are other ways, I preferred to keep his reasoning, adding in foreach:

• for every time he meets a $value empty, it adds a space, otherwise it takes the value in the variable $morse.
• in the end, it clears out unnecessary spaces by printing HEY JUDE instead of HEY JUDE.

<?php

    function morse($mensagem) {
    
        $morse = [
            'A' => '.-', 
            'B' => '-...', 
            'C' => '-.-.', 
            'D' => '-..', 
            'E' => '.', 
            'F' => '..-.', 
            'G' => '--.', 
            'H' => '....', 
            'I' => '..', 
            'J' => '.---' , 
            'K' => '-.-', 
            'L' => '.-..', 
            'M' => '--',
            'N' => '-.', 
            'O' => '---', 
            'P' => '.--.', 
            'Q' => '--.-', 
            'R' => '.-.', 
            'S' => '...', 
            'T' => '-', 
            'U' => '..-',
            'V' => '...-',
            'W' => '.--',
            'X' => '-..-',
            'Y' => '-.--',
            'Z' => '--..'
        ];
    
        $saida = '';
        $letras = preg_split("/\s/", $mensagem);
        
        foreach ($letras as $value) {
        
            $saida .= !empty($value) ? array_search($value, $morse) : ' ';
        }
            
        return preg_replace("/\s{2,}/", " ", $saida);
    }
    
    echo morse(".... . -.--   .--- ..- -.. .");

Paying attention to the foreach, in this case, you do not need to pass the array id, since the query is based on the $value.

Answer 2

Weverton, make it easy, make it 2 explodes: the first with 3 spaces as separator (which will divide the message into words) and a second explodes with 1 space as separator (which will divide the word into letters).

Your code would look like below. I modified the array to not need the array_search and used the ?? for the case of nonexistent morse code, it include the code itself in the output (modify as you wish).

<?php
$morse = [
        '.-' => 'A', 
        '-...' => 'B', 
        '-.-.' => 'C', 
        '-..' => 'D', 
        '.' => 'E', 
        '..-.' => 'F', 
        '--.' => 'G', 
        '....' => 'H', 
        '..' => 'I', 
        '.---' => 'J' , 
        '-.-' => 'K', 
        '.-..' => 'L', 
        '--' => 'M',
        '-.' => 'N', 
        '---' => 'O', 
        '.--.' => 'P', 
        '--.-' => 'Q', 
        '.-.' => 'R', 
        '...' => 'S', 
        '-' => 'T', 
        '..-' => 'U',
        '...-' => 'V',
        '.--' => 'W',
        '-..-' => 'X',
        '-.--' => 'Y',
        '--..' => 'Z'
    ];
    
    $saida = '';
    $mensagem = ".... . -.--   .--- ..- -.. .";

    //Divide mensagem em palavras
    $palavras = explode('   ', $mensagem);
    foreach ($palavras as $palavra) {
        
        //Divide palavra em "letras morse"
        $letras = explode(' ', $palavra);
        foreach ($letras as $letra)
        {
            //Converte "letra morse" para letra do alfabeto e concatena na saída
            $saida .= $morse[$letra] ?? $letra;
        }
        
        //Adiciona espaço para separar as palavras na saída
        $saida .= ' ';
    }
        
    //Tira espaço extra ao final
    $saida = trim($saida);
    
    //Exibe resultado
    echo $saida;
?>