With each column you can define set of search operators and first one become default. e.g.

(e.g. bw = begins with, 'eq','ne','lt','le','gt','ge','bw','bn','in','ni','ew','en','cn','nc')

$col["searchoptions"]["sopt"] = array("cn","bw"); // only show contains and beginswith with first as default.
$cols[] = $col;