has_sub_field()

Description
This function is deprecated. Please use the have_rows() function instead.
This function is used within a while-loop to loop through each row of a Repeater or Flexible Content field.
Unlike 
have_rows(), this function will take a step through the available rows each time it is called, causing undesired results when also used within an if-statment.
Parameters
has_sub_field( $field_name, $post_id );
$field_name (string) (Required) The name of the Repeater or Flexible Content field to be retrieved. e.g. ‘gallery_images’
$post_id (mixed) (Optional) The post ID where the value is saved. Defaults to the current post.
Return
(bool) True if a row exists.
Change Log
Deprecated in version 4.3.0
Examples
Loop through Repeater field
This example demonstrates how to loop through a repeater field called “gallery_images”.
<?php if( get_field('gallery_images') ): ?>
    <?php while( has_sub_field('gallery_images') ): ?>
        <img src="<?php the_sub_field('image'); ?>" alt="<?php the_sub_field('alt'); ?>" />
    <?php endwhile; ?>
 <?php endif;
Loop through a Flexible Content field
This example demonstrates how to loop through a Flexible Content field called “content” and display various layouts.
<?php while( has_sub_field("content") ): ?>
    <?php if( get_row_layout() == "paragraph" ): ?>
        <div>
            <?php the_sub_field("content"); ?>
        </div>
    <?php elseif( get_row_layout() == "file" ): ?>
        <div>
            <a href="<?php the_sub_field("file"); ?>" ><?php the_sub_field("name"); ?></a>
        </div>
    <?php elseif( get_row_layout() == "featured_posts" ): ?>
        <div>
            <h2><?php the_sub_field("title"); ?></h2>
            <?php the_sub_field("content"); ?>
            <?php if( get_sub_field("posts") ): ?>
                <ul>
                <?php foreach( get_sub_field("posts") as $p ): ?>
                    <li><a href="<?php echo get_permalink($p->ID); ?>"><?php echo get_the_title($p->ID); ?></a></li>
                <?php endforeach; ?>
                </ul>
            <?php endif; ?>
        </div>
    <?php endif; ?>
<?php endwhile; ?>
Loop through nested Repeater fields
This example demonstrates how to loop through nested Repeater fields and display the sub field data.
<?php if( get_field('parent_repeater') ): ?>
    <?php while( has_sub_field('parent_repeater') ): ?>
        <div>
            <?php if( get_sub_field('child_repeater') ): ?>
                <ul>
                <?php while( has_sub_field('child_repeater') ): ?>
                    <li><?php the_sub_field('item'); ?></li>
                <?php endwhile; ?>
                </ul>
            <?php endif; ?>
        </div>  
    <?php endwhile; ?>
<?php endif;
Loop through nested Repeater fields (from another $post ID)
This example demonstrates how to loop through nested Repeater fields from a different post with the ID of 123.
Note: You don’t need to specify the 
$post_id for any sub field functions.
<?php if( get_field('parent_repeater', 123) ): ?>
    <?php while( has_sub_field('parent_repeater', 123) ): ?>
        <div>
            <?php 
            if( get_sub_field('child_repeater') ): ?>
                <ul>
                <?php while( has_sub_field('child_repeater') ): ?>
                    <li><?php the_sub_field('item'); ?></li>
                <?php endwhile; ?>
                </ul>
            <?php endif; ?>
        </div>  
    <?php endwhile; ?>
<?php endif;