Please help me with this small php line

Hello guys,

Maybe someone can help me with this small peace of code

I have this code:

<?php echo get_field( "twitter",$modelID); ?>

PHP:

If I don't have anything in my "twitter" field, doesnt appear nothing.
If I have something in my "twitter" field appears this code:

<a href="#" target="_blank"><img src="http://mydomain.com/wp-content/uploads/2016/01/twitter-24.png" alt="Official Twitter" title="Official Twitter"></a>

Code (markup):

Everything is working fine here, but I like to ask if is possible to integrate the html code in the first line of php above

The idea is to show twitter url using the first php code and replace the # in the href with the twitter url.

I know that can be difficult to understand what I want lol, but if you have trouble understanding or if you have any doubt, please let me know and I will try to explain with another words.

Hope someone can help me, thank you guys

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Thinking better, I want to use this code:

<a href="<?php echo get_field( "twitter",$modelID); ?>" target="_blank"><img src="http://mydomain.com/wp-content/uploads/2016/01/twitter-24.png" alt="Official Twitter" title="Official Twitter"></a>

PHP:

But I only want to show if my custom field "twitter" is filled.
Is it possible?

 

Solved

With the following code:

<?php if ( get_post_meta($post->ID, 'twitter', true) ) { ?><a target="_blank" href="<?php echo get_post_meta($post->ID, "twitter", $single = true); ?>"><img src="http://mydomain.com/wp-content/uploads/2016/01/twitter-24.png" alt="<?php the_title(); ?> Official Twitter" title="<?php the_title(); ?> Official Twitter" /></a><?php } ?>

PHP:

Thank you anyway guys