How to echo a function only if variable has a value?

How can I echo this function:

            <?php echo  "€" . get_post_meta( get_the_ID(), 'deal_sale_price', true ); ?>

PHP:

only if 'deal_sale_price' has a value?

Thanks a lot.

 

Since this is a WP question, I'm not 100% sure this will work, but it might:

<?php 
if (!empty(get_post_meta(get_the_ID(),'deal_sale_price',true))) {
    echo "€" . get_post_meta( get_the_ID(), 'deal_sale_price', true ); 
}
?>

PHP:

 

Not confident with PHP at all, just starting to learn bits of it actually. Anyway Thanks a lot guys, both worked

 

Legibility nothing, if you're gonna call a procedure more than once, STORE THAT PUPPY!

I'd also advise against the string addition, "curly brackets for nothing", double quotes on a non-parse string.. and you could do the assignment and the check as a single operation.

<?php

if (!empty(
	$deal_sale_price = get_post_meta(get_the_ID(),'deal_sale_price',true)
)) echo '€', $deal_sale_price;

?>

Code (markup):

Remember, comma delimited echo is faster than string addition, uses less memory, and actually will run in the order you coded it.

Just saying... goes with my general belief that 99% of the time people use string addition or double quotes on a string, they're doing something WRONG.

 

<?php

function Check( $value )
{
      if ( strlen($value) && is_string($value) )
      {
            return true;
      }
      else
      {
            return false;
      }
}

if Check(get_post_meta( get_the_ID(), 'deal_sale_price', true ))
    echo get_post_meta( get_the_ID(), 'deal_sale_price', true );

?>

Code (markup):

 

Why in the world would you create a separate function for this? *shakes head*

 

... and one with an if statement at that... Must just be a chubby chaser with a love of bloat like that.