How to invert words and count total characters

Question

As I do via php/html, for example, I have a input for user to type anything, and the time he clicks on the "OK" button, I return the word he typed in reverse, and the amount of characters of the word he typed in?

I know I’ll have to use the methods strlen() and strrev(), but I can’t do it. Can someone help me? Grateful

Answer 1

If Encode (ISO-8859-1) is configured correctly the functions strlen() and strrev() work as expected, if using UTF-8 prefer the approach below.

stlen() Does not count the number of characters but the byte, a practical example is input ação returns 6(bytes) and not 4(characters), for multibite encoding characters use mb_strlen().

strrev() suffers from the same problem, does not treat multibyte characters so does not do the inversion correctly, in which case use regex to solve the job.

Example with strlen() & strrev()

$str = 'AÇÃO';
printf("%s - %s caracteres - invertido: %s", $str, strlen($str), strrev($str));

Satida:

AÇÃO - 6 caracteres - invertido: O�Ç�A

Example with regex & mb_strlen()

function mb_strrev($str){
    preg_match_all('/./us', $str, $ar);
    return implode('', array_reverse($ar[0]));
}

$str = 'AÇÃO';
printf("%s - %s caracteres - invertido: %s", $str, strlen($str), strrev($str));

Satida:

AÇÃO - 4 caracteres - invertido: OÃÇA

Answer 2

I suggest something like this:

 $input = $_GET['nome_do_campo'];
 $invertido = strrev($input);
 $tamanho = strlen($input);

echo "String invertida: <em>{$invertido}</em>. O tamanho é de <strong>{$tamanho}</strong> caracteres";

Answer 3

Simple

<?php

    $string = (isset($_POST['input1'])) ? trim($_POST['input1']) : null;

    $stringInvertida = strrev($string);
    $qntCaracteres = strlen($string);

    echo "Seu texto invertido é: {$stringInvertida} e contem {$qntCaracteres} caractere(s).";

In your HTML form, set the name do input that will receive the string as input1

Answer 4

A multibyte character support version:

$str = '日本語'; // teste essa palavra alienígena
$str = 'Ação'; // ou será que essa palavra é alienígena?

echo 'quantidade de letras: '.mb_strlen($str);
echo PHP_EOL.'<br />inverso: '.join('', array_reverse(preg_split('~~u', $str, -1, PREG_SPLIT_NO_EMPTY)));

The native function strrev() is not "multibyte safe", so the implementation using join(), array_reverse() and preg_split().

The function mb_strlen() is multibyte character specific and returns the number of characters. Do not confuse with number of bytes.

If you want to know the amount of bytes, use strlen().

See the difference

$str = 'Ação';
echo strlen($str).PHP_EOL.'<br />';
echo mb_strlen($str).PHP_EOL;