How to avoid adding a comma at the last row? - php

Question

I use the following code to add a comma , at the end of every filename. After this using explode i put the rows on an array.
The images array if I echo it, it shows a.jpg,b.jpg,c.jpg, (please mind the last comma at the end of c.jpg)
How can I avoid adding a comma to the last found row?
<?php
while($image = mysql_fetch_array($images)) {
$images_path .= $image['FILE_NAME'].',';
}
$images_array = explode(",", $images_path);
?>

Answer 1

Make use of rtrim() by providing a comma as the second paramter as character mask
$images_path = rtrim($images_path,","); //<---- The added code
$images_array = explode(",", $images_path);

Answer 2

Why add it to a string and then convert it to an array, if you can add it straight away?
$images_array = array();
while($image = mysql_fetch_array($images)) {
$images_array[] = $image['FILE_NAME'];
}

Answer 3

You do this:
Create your required string
Knowingly introduce a problem that can easily be avoided
Fix the issue you created with more code (generate your required array by splitting the string)
Instead, do this:
Create the required array as you want it, first time
Your current approach will create more problems as your coding style improves, and you have more complex code and are reusing your code (ie this would be in a class).
Like this:
<?php
while($image = mysql_fetch_array($images))
{
$images_array[] = $image['FILE_NAME'];
}
?>
Instead of, how you currently do it, setting a variable with the data from the database, with a comma separating each value (and a rouge one at the end as a result), then exploding the variable into an array, and wanting to remove the end comma..
Just set the array in the first place!

Answer 4

The simplest way from the code you supplied would be
explode(',', $images_path, -1);
in most cases you might reconsider if you really need a string which has been constructed in such a way.

Answer 5

There are going to be a dozen ways to tackle this, some pretty, some not.
Ideally, this is why you use libraries like Apache / Google commons in production code, so that there is standard ways to do things like implode / explode ; split / join; or whatever its called in the language you are in.
With that said, maybe you are writing base code or provide this as a library or maybe just want to know how you handle this.
I don't care for the trim options, they are destructive and you will find yourself one day when you depend upon things of that nature, staring at a code review or debugging a problem and thinking, oh this trim, substring whatever is making assumptions and messing things up, which when in base / shared code is bad to be making.
I would handle this in a more deterministic way of:
(pseudocode)
<?php
$images_path = "";
// Base case
if($image = mysql_fetch_array($images)) {
$images_path .= $image['FILE_NAME'];
}
// If multiple results, iterate
while($image = mysql_fetch_array($images)) {
$images_path .= ',' . $image['FILE_NAME'];
}
$images_array = explode(",", $images_path);
?>
Switch it from appending the , to prepending the comma when there are multiple. Now you never have to remove an extra comma or do any destructive command. Very similar how doing a proof you build a base case and then build on the base.