还原字符串并替换字符-RegP with Php

Question

I have a doubt again on RegEx in Php.

Assume that I have a line like this

716/52  ; 250/491.1; 356/398; 382/144

I want the output to be

1. Replace all semi-colon with comma. I think I can do this using

    $myline= str_replace(";", ",", $myline); 

2. Interchange the numbers and replace '/' with a comma. That is, 716/52 will become 52,716. This is where I get stuck.

So, the output should be

52,716 , 491.1,250, 398,356, 144,382

I know that using sed, I can achieve it as

1,$s/^classcode:[\t ]\+\([0-9]\+\)\/\([0-9]\+\)/classcode: \2\,\1/

But, how do I do it using preg_match in php?

Answer 1

$str = '716/52  ; 250/491.1; 356/398; 382/144';

$str = str_replace(';', ',', $str);

$res = preg_replace_callback('~[\d.]+/[\d.]+~', 'reverse', $str);

function reverse($matches)
{
    $parts = explode('/', $matches[0]);
    return $parts[1] . ',' . $parts[0];
}

var_dump($res);

And working sample: http://ideone.com/BeS9j

UPD : PHP 5.3 version with anonymous functions

$str = '716/52  ; 250/491.1; 356/398; 382/144';

$str = str_replace(';', ',', $str);

$res = preg_replace_callback('~[\d.]+/[\d.]+~', function ($matches) {
    $parts = explode('/', $matches[0]);
    return $parts[1] . ',' . $parts[0];
}, $str);

var_dump($res);

Answer 2

As an alternative to Regexen you could try this:

echo join(', ', array_map(
     function ($s) { return join(',', array_reverse(explode('/', trim($s)))); },
     explode(';', $string)));

Answer 3

$str = '716/52  ; 250/491.1; 356/398; 382/144';
$str = preg_replace('(\d+(?:\.\d+)?)\/(\d+(?:\.\d+)?)', '$2,$1', $str);
$str = str_replace(';', ',', $str);

Uses two capture groups, replacing them in reverse order. See it here .