proc lintersect {a b} { foreach e $a { set x($e) {} } set result {} foreach e $b { if {[info exists x($e)]} { lappend result $e } } return $result } proc lunion {a b} { foreach e $a { set x($e) {} } foreach e $b { if {![info exists x($e)]} { lappend a $e } } return $a } proc ldifference {a b} { foreach e $b { set x($e) {} } set result {} foreach e $a { if {![info exists x($e)]} { lappend result $e } } return $result } proc in {list element} { expr {[lsearch -exact $list $element] != -1} }
MJ - Using 8.5 ni and in, this can be speeded up quite considerable, for instance:
proc ldifference2 {a b} { set result {} foreach e $a { if {$e ni $b} {lappend result $e} } return $result }[zashi] - The above example using ni doesn't work if $b has more elements than $a. APN I think you are confusing the difference operation. It returns A-B, i.e. all elements of A that are not also in B. It is not "all values that are in A or B but not both".You can also use lmap to make this more concise. But then to fix the length issue it gets bigger again
proc ldifference3 {a b} { if {[llength $a] > [llength $b]} { return [lmap e $a {if {$e ni $b} {set e} else continue}] } else { return [lmap e $b {if {$e ni $a} {set e} else continue}] } }