Create a unique ID to easily identify repeater field’s rows

Use this code for create a unique ID for each Advanced Custom Fields Repeater Fields.

<?php if( have_rows('repeater_field') ): $i = 0; ?>
	<div class="repeater_loop2">
	<?php while( have_rows('repeater_field') ): the_row(); $i++; ?>
		<div class="content-bluck" id="block-<?php echo $i; ?>">
			<h2>#div (repeater <?php echo $i; ?>)</h2>
			<h3><?php the_sub_field('subfield3');?></h3>
			<p><?php the_sub_field('subfield4'); ?></p>
		</div>
	<?php endwhile; ?>
	</div>
<?php endif; ?>