set

set(n)                        Tcl Data Structures                       set(n)



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NAME
       set - Procedures for manipulating sets

SYNOPSIS
       package require Tcl  8.0

       package require struct  ?2.0?

       ::struct::set empty set

       ::struct::set size set

       ::struct::set contains set item

       ::struct::set union ?set1...?

       ::struct::set intersect ?set1...?

       ::struct::set difference set1 set2

       ::struct::set symdiff set1 set2

       ::struct::set intersect3 set1 set2

       ::struct::set equal set1 set2

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DESCRIPTION
       The  ::struct::set  namespace contains several useful commands for pro-
       cessing finite sets.

       It exports only a single command, struct::set. All  functionality  pro-
       vided here can be reached through a subcommand of this command.

COMMANDS
       ::struct::set empty set
              Returns  a  boolean value indicating if the set is empty (true),
              or not (false).

       ::struct::set size set
              Returns an integer number greater than or equal to zero. This is
              the number of elements in the set. In other words, its cardinal-
              ity.

       ::struct::set contains set item
              Returns a boolean value indicating if the set contains the  ele-
              ment item (true), or not (false).

       ::struct::set union ?set1...?
              Computes  the set containing the union of set1, set2, etc., i.e.
              "set1 + set2 + ...", and returns this set as the result  of  the
              command.

       ::struct::set intersect ?set1...?
              Computes  the  set  containing  the  intersection of set1, set2,
              etc., i.e. "set1 * set2 * ...", and  returns  this  set  as  the
              result of the command.

       ::struct::set difference set1 set2
              Computes  the  set  containing  the difference of set1 and set2,
              i.e. ("set1 - set2") and returns this set as the result  of  the
              command.

       ::struct::set symdiff set1 set2
              Computes the set containing the symmetric difference of set1 and
              set2, i.e. ("(set1 - set2) + (set2 - set1)")  and  returns  this
              set as the result of the command.

       ::struct::set intersect3 set1 set2
              This  command is a combination of the methods intersect and dif-
              ference.    It   returns   a   three-element   list   containing
              "set1*set2",  "set1-set2",  and  "set2-set1",  in this order. In
              other words, the intersection of the  two  parameter  sets,  and
              their differences.

       ::struct::set equal set1 set2
              Returns  a  boolean  value  indicating if the two sets are equal
              (true) or not (false).

REFERENCES
KEYWORDS
       cardinality, difference, emptiness, intersection, membership, set, sym-
       metric difference, union

COPYRIGHT
       Copyright (c) 2004 Andreas Kupries <andreas_kupries AT users.net>



struct                                2.0                               set(n)