Custom Field add markup to line breaks

Question

I am looking for a solution to add markup to a custom field with multiple lines. Much like wpautop, but with customization. I'm not quite sure to approach this with a custom function or something built into WordPress.

Custom Field text would be:

Line 1
Line 2
Line 3

Code output would add markup:

<span>Line 1</span>
<span>Line 2</span>
<span>Line 3</span>

Answer 1

I believe this is what you are after:

// define $post_id, $key, $single
$multipleLineValue = get_post_meta($post_id, $key, $single);

// Convert into an array where desired code can be added to the output
$multipleLineValue = explode("\n",$multipleLineValue);
$output = "";
foreach ($multipleLineValue as $lineValue) {
   $output .= "<span>".$lineValue."</span><br>";
}
echo $output;