set counts(heads) 0 set counts(tails) 0 set counts(edge) 0 for {set i 0} {$i < 1000} {incr i} { set result [expr {rand()*2.01}] if {$result > 2} { set result edge } elseif {$result > 1} { set result heads } else { set result tails } incr counts($result) } parray counts