I've got a bunch of $_POST values being brought over from a form. Many of these values are from checkboxes, with the form names all starting with 'field_'. These signify the columns in a chart that ...

Each pass through the data consists of making a set of comparisons between two data items. You always start with the items in position 0 and 1, then 1 and 2, then 2 and 3 etc. Each time, you compare ...