PHP如何将if语句放在echo块内

Question

I have the following if statement:

<?php if ( isset ( $prfx_stored_meta['wedding-user'] ) ) selected( $prfx_stored_meta['wedding-user'][0], 'select-one' ); ?>

which I need to insert into this echo statement:

$users = get_users();
$i = 0;
// Array of WP_User objects.
foreach ( $users as $user ) {
    echo "<option value='select-$i' >" . esc_html( $user->display_name ) . "</option>";
    $i++;
}

Just before closing the <option> tag
I'm not sure how to add an if statement inside of an echo

Answer 1

Don't.

Ignoring for a moment that outputting your HTML embedded inside echo statements like this is an anti-pattern (consider using a templating engine!), you will make your code really hard to read by mixing your logic and your content even more, which you will be doing if you employ the conditional operator * here.

In fact, in general, if you have anything more than basic string interpolation in your output statements, you're not separating your logic and content enough.

Here, it will look something like this:

$users = get_users();
$i = 0;
// Array of WP_User objects.
foreach ( $users as $user ) {
   echo "<option value='select-$i' ";
   if (isset($prfx_stored_meta['wedding-user']))
      echo selected($prfx_stored_meta['wedding-user'][0], 'select-one');
   echo ">" . esc_html( $user->display_name ) . "</option>";

   $i++;
}

See how messy it is? And with a long line using the conditional operator it would be even worse !

_{* Not the "ternary operator"! Being "ternary" is its arity, not its name.}

Answer 2

You have to use ternary operator : www.php.net/ternary

Try this :

echo "<option value='select-$i' >" . esc_html( $user->display_name ) . ((isset($prfx_stored_meta['wedding-user'])?selected( $prfx_stored_meta['wedding-user'][0], 'select-one'):'')."</option>";

Source : if block inside echo statement?

Answer 3

您将需要使用一个三元运算符，该运算符用作缩短的IF / Else语句。