How to use echo do_shortcode with dynamic variable?

You’re close to right, but this should be what you’re after (note, I haven’t tested this.. it’s just cut-and-paste):

<?php echo do_shortcode('[walkscore ws_wsid="example" ws_address="'.get_post_meta($post->ID, 'pyre_full_address', true).'"]'); ?>

If that doesn’t work I’d guess that the get_post_meta() call isn’t working properly, so you could try this for some de-bugging:

<?php $val = get_post_meta($post->ID, 'pyre_full_address', true);
echo "<p>Val: '".$val."'</p>";
echo do_shortcode('[walkscore ws_wsid="example" ws_address="'.$val.'"]'); ?>

I think I can see where you went wrong looking back at it now.

When you use strings with single-quotes like ‘Hi, ho ware you?’, they are just parsed as they are, nothing is done with them. When you use double-quotes like “Hello, how are you?” the string is parsed to check for variables. As you were using single-quotes, PHP won’t look inside the string to see if there’s any variables in it.

That’s why I always set any variables or functions or anything else that’s not actually a set part of the string outside of the actual string like I’ve shown.

echo "There are ".count ($sheep)." sheep.";

That way it doesn’t matter if you’re using single or double quotes, the values will always work correctly. It also helps readability when you’re using an editor with syntax colouring.