删除小数，跟随数字并舍入值

I have the following data.

$96.2k
$75.2k
$44.4k
$35.6k
Etc.......

What I am wanting to do is replace the decimal and any number(s) following the decimal. Then i want to round the whole number to the nearest tenth.

All of my data is between 10k and 90k

So the expected output would be..

$100k
$80k
$40k
$40k

I know i can use preg_replace('/\.[0-9]+/', '', $data); to remove the decimal and numbers but can i not use regular preg_replace with a function?

<?php

$number = '$96.2k';

$number = str_replace(array('$', 'k'), '', $number);
$number = round($number, -1); // -1 rounds to nearest 10

echo '$' . $number . 'k';
// $100k    

?>

More info on round here: http://php.net/manual/en/function.round.php

Instead of using preg_replace, I would use preg_replace_callback:

$data = preg_replace_callback('/([0-9]+)\.[0-9]+/',   # capture first group of digits
      function($m) {                                  # $m is your captured match
         return round($m[1], -1);                     # round our captured match
      }, $data);

The will round your match ($m) to the nearest 10. Have a look at round for the use of parameters.

See working demo