PHP replace string

$name (string) gives something like (possible value):

John II, Litten Draw

We should update $name in two steps:

1. Catch the words before first comma and throw them to the end of the string
2. Remove first comma
3. Create a file current_name.txt (or update if already exists) and throw to it source of $name

"John II, Litten Draw" should be replaced with "Litten Draw John II".

Thanks.

Like this?

$split = explode(",", $name, 1);
$name = trim($split[1]) . " " . trim(split[0]);

Then it's just basic file I/O.

If you have a list of words (assuming they are all on separate lines):

$list = explode("\n", $names);
$nnames = "";
foreach($list as $name)
{
        $split = explode(",", $name);
        $nnames .= trim($split[1]) . " " . trim(split[0]) . "\n";
}

This regex should do it for you...

preg_replace('#\\b(\\w+),\\s*(\\w+)\\b#', '\\2 \\1', $string);

Basically, it's looking for:

1. A word boundry (the \\b part)
2. Then one or more word characters (the \\w+ part)
3. Then a comma followed by zero or more whitespace characters (,\\s*)
4. Then one or more word characters (the \\w+ part)
5. Finally, another word boundry...

regular expressions are the way to go here

$a = "Obama, Barak";
echo preg_replace('~(\w+)\W+(\w+)~', "$2 $1", $a);

also works for multiple names:

$a = "
Obama, Barak
Federer, Roger
Dickens, Charles
";

echo preg_replace('~(\w+)\W+(\w+)~', "$2 $1", $a);

Here's some sample code that should work OK:

<?php

    function getCanonicalName($name) {

        // Check for the existance of a comma and swap 'elements' if necessary.
        if(strpos($name, ',') !== false) {
            list($surname, $forename) = explode(',', $name);
            $name = $forename . ' ' . $surname; 
        }

        // Trim the name.
        return trim($name);
    }   


    // Test data and file I/O.
    $outputData = '';
    $testData = array('Obama, Barak', 'Federer, Roger', 'John Parker');

    foreach($testData as $name) {
        $outputData .= getCanonicalName($name) . "\n";
    }


    file_put_contents('current_name.txt', $outputData, FILE_APPEND);
?>

Incidentally, this (like all of the solutions currently attached to your question) will cause data loss if there's more than one comma in $name. As such, if this is possible you should update getCanonicalName to cater for this eventuality.

See strpos to find the comma, ltrim to remove the whitespace, and fopen with the mode a to append to the file. You can also use explode to split around the comma, which is usually easier