Add comma after value only if more than one value? - php

Question

Im trying to echo a set of values for categories. What I'd like to do is if there are more than one value, append a comma afterwards. Here's a snippet of what I have:
<?php foreach((get_the_category()) as $category) { echo $category->cat_name . ', '; } ?>
The problem with this is that categories with one value will have a comma at the end.

Answer 1

Alternative 1
Add all values to an array and then just use implode() to glue them all together:
$catArray = [];
foreach((get_the_category()) as $category) {
$catArray[] = $category->cat_name;
}
// Now we can implode the array, using , as the glue
echo implode(', ', $catArray);
Alternative 2
You could also prepend the commas in your loop so you don't need any if-statements:
$glue = '';
foreach((get_the_category()) as $category) {
echo $glue . $category->cat_name;
$glue = ', ';
}
or a shorter version (not as readable though and requires PHP 7+):
foreach((get_the_category()) as $category) {
echo ($glue ?? '') . $category->cat_name;
$glue = ', ';
}
The first iteration won't get any comma in front of it, but the rest will.

Answer 2

You could get the count of results from get_the_category(), set a counter and increment that each time through the loop. Check if $i is equal to the count and if it is, don't add the comma.
Assuming that function is countable and you don't need checks to make sure their aren't 0 results:
<?php
$count = count(get_the_categories());
$i = 1;
foreach((get_the_category()) as $category) {
if($i < $count) {
echo $category->cat_name . ', ';
} else {
echo $category->cat_name;
}
$i++;
}
?>