How do I remove a comma off the end of a string?

I want to remove the comma off the end of a string. As it is now I am using

$string = substr($string,0,-1);

but that only removes the last character of the string. I am adding the string dynamically, so sometimes there is no comma at the end of the string. How can I have PHP remove the comma off the end of the string if there is one at the end of it?

Solution 1:

$string = rtrim($string, ',');

Docs for rtrim here

Solution 2:

This is a classic question, with two solutions. If you want to remove exactly one comma, which may or may not be there, use:

if (substr($string, -1, 1) == ',')
{
  $string = substr($string, 0, -1);
}

If you want to remove all commas from the end of a line use the simpler:

$string = rtrim($string, ',');

The rtrim function (and corresponding ltrim for left trim) is very useful as you can specify a range of characters to remove, i.e. to remove commas and trailing whitespace you would write:

$string = rtrim($string, ", \t\n");

Solution 3:

i guess you're concatenating something in the loop, like

foreach($a as $b)
  $string .= $b . ',';

much better is to collect items in an array and then join it with a delimiter you need

foreach($a as $b)
  $result[] = $b;

$result = implode(',', $result);

this solves trailing and double delimiter problems that usually occur with concatenation

Solution 4:

If you're concatenating something in the loop, you can do it in this way too:

$coma = "";
foreach($a as $b){
    $string .= $coma.$b;
    $coma = ",";
}