[php] if block inside echo statement?

In sake of readability it should be something like

<?php 
  $countries = $myaddress->get_countries();
  foreach($countries as $value) {
    $selected ='';
    if($value=='United States') $selected ='selected="selected"'; 
    echo '<option value="'.$value.'"'.$selected.'>'.$value.'</option>';
  }
?>

desire to stuff EVERYTHING in a single line is a decease, man. Write distinctly.

But there is another way, a better one. There is no need to use echo at all. Learn to use templates. Prepare your data first, and display it only then ready.

Business logic part:

$countries = $myaddress->get_countries();
$selected_country = 1;    

Template part:

<? foreach($countries as $row): ?>
<option value="<?=$row['id']?>"<? if ($row['id']==$current_country):> "selected"><? endif ?>
  <?=$row['name']?>
</option>
<? endforeach ?>