Question

I have a while loop issue in PHP that seems like it could have been solved using the ampersand sign to make it a reference if it were elsewhere. Below is an example. I’m trying to append _n to the filename (in the basename). If there’s _1 then I want it to be _2, if there’s _2 I want it to be _3 and so on. For some reason I can’t update the $filename variable in the condition so I think it’s not getting changed in the loop.

$dir = 'images';
$filename = '123.jpg';
$i = 0;
while (file_exists($dir.'/'.$filename)) {
    $filename = preg_replace('/^(\d*?)(\.jpg)$/',"$1_".(++$i)."$2",$filename);
}
echo $filename;

What am I doing wrong?

Answer 1

It looks like your regex is a little off, and you are not capturing the _n if it already exists.

while (file_exists($dir.'/'.$filename)) {
  $filename = preg_replace('/^(\d+)(.*)(\.jpg)$/',"$1_".(++$i)."$3",$filename);
  //-------------------------------^^^^ Capture the _n if it exists
  // And stick the number in with $1 and $3 (now the .jog)
}
echo $filename;

// Current files...
123_1.jpg
123_2.jpg
123.jpg

// Outputs 123_3.jpg