I was trying with different versions of this code, but I got fatal error from wp when the code activated:
if( have_rows(‘testrepeater’) ) {
$i = 0;
while( have_rows(‘testrepeater’) ) {
the_row();
$i++;
$subfield_key_var = get_sub_field(‘pagelink_testfield’);
update_sub_field(‘url_testfield’, ‘$subfield_key_var’);
}
}