How to echo a different field if another field is empty?

Question

I succeeded in getting both images and video to echo into a bootstrap carousel. However, I run into a problem when the post contains no images. If there are no images then there is no class="item active" so the bootstrap carousel won't show.

Here is my workaround I feel like I'm almost there, can someone give me a hand?

<?php $myCarousel = get_order_field('projectdetails_image'); // use the Custom Group name 
        if( !empty( $myCarousel )) {
                foreach($myCarousel as $carousel){
                            if ($counter == 0) {
                                echo "<div class='item active'>";
                                echo '<img src="';
                                echo get('projectdetails_image',1,$carousel);
                                echo '"/>';
                                echo "</div>";
                            }
                            else{
                                echo "<div class='item'>";
                                echo '<img src="';
                                echo get('projectdetails_image',1,$carousel);
                                echo '"/>';
                                echo "</div>";
                            }
                            $counter++;

                $videos = get_order_field('video_vimeo');
                foreach($videos as $video){
                    if ( get('video_vimeo',TRUE) ) {
                            echo "<div class='item black'><div id='video-wrap'>";
                            echo get('video_vimeo',1,$video);
                            echo "</div></div>";
                    }
                    else {}
                }
                }   
        }
        else{            
                $videos = get_order_field('video_vimeo');
                foreach($videos as $video){
                    if ( get('video_vimeo',TRUE) ) {
                            echo "<div class='item active black'><div id='video-wrap'>";
                            echo get('video_vimeo',1,$video);
                            echo "</div></div>";
                    }
                    else {}
                }   
        }?>

Got it finally:

    <?php $myCarousel = get_order_field('projectdetails_image'); // use the Custom Group name 
if( !empty( $myCarousel )) {
        foreach($myCarousel as $carousel){
        $myimg = get('projectdetails_image',1,$carousel);
        if ( !$myimg ) {
        $videos = get_order_field('video_vimeo');
        foreach($videos as $video){
            if ( get('video_vimeo',TRUE) ) {
                    echo "<div class='item active black'><div id='video-wrap'>";
                    echo get('video_vimeo',1,$video);
                    echo "</div></div>";
            }
            else {}
        }   
        }
        if ( $myimg ) {
            echo "<div class='item".( $counter == 0 ? ' active' : '' )."'>";
            echo '<img src="';
            echo $myimg;
            echo '"/>';
            echo "</div>";
            $counter++;

            $videos = get_order_field('video_vimeo');
            foreach($videos as $video){
            if ( get('video_vimeo',TRUE) ) {
                echo "<div class='item black'><div id='video-wrap'>";
                echo get('video_vimeo',1,$video);
                echo "</div></div>";
            }}
        }
    }
}
else{            
        $videos = get_order_field('video_vimeo');
        foreach($videos as $video){
            if ( get('video_vimeo',TRUE) ) {
                    echo "<div class='item active black'><div id='video-wrap'>";
                    echo get('video_vimeo',1,$video);
                    echo "</div></div>";
            }
            else {}
        }   
}?>

Answer 1

You might try to replace the foreach( $myCarousel as $carousel ) with:

foreach($myCarousel as $carousel){
    $myimg = get('projectdetails_image',1,$carousel);
    if ( !$myimg ) {
        // use this if you want to show a default image when no image is available in the post
        $myimg = get_template_directory_uri().'/images/default_banner.jpg';
    }
    if ( $myimg ) {
        echo "<div class='item".( $counter == 0 ? ' active' : '' )."'>";
        echo '<img src="';
        echo $myimg;
        echo '"/>';
        echo "</div>";
        $counter++;

        $videos = get_order_field('video_vimeo');
        foreach($videos as $video){
            if ( get('video_vimeo',TRUE) ) {
                echo "<div class='item black'><div id='video-wrap'>";
                echo get('video_vimeo',1,$video);
                echo "</div></div>";
            }
        }
    }
}