webcreator.me

これで行の最大値を取得できます。

<?php get_sub_field('grid_block'); ?>

このように変数に代入して使えます。

<?php if (have_rows('food_free_repeater')): ?>
  <?php while (have_rows('food_free_repeater')): the_row();  ?>
    <p class="circle01"><?php the_sub_field('food_free_ttl'); ?></p>
    <div><?php the_sub_field('food_free_content'); ?></div>
    
    <?php $max_counter = count(get_sub_field('food_child_free_repeater')); ?>
    <div class="flex_block">
      <?php if (have_rows('food_child_free_repeater')): ?>
      <?php $count = 1; ?>
      <?php while (have_rows('food_child_free_repeater')): the_row();  ?>

        <div class="flex_box <?php if ($count == $max_counter && $max_counter%2 !== 0  ): ?> box100 <?php endif; ?> ">
          <p class="flex_box_ttl"><?php the_sub_field('food_child_ttl'); ?></p>
          <div>
            <?php the_sub_field('food_child_txt'); ?>
          </div>
        </div>
        

      <?php $count++; ?>
      <?php endwhile; ?>
      <?php endif; ?>
    </div>
    
　　<?php endwhile; ?>
<?php endif; ?>

参考サイト

Count total number of repeater rows