REBOL Document

Union - Function Summary


Creates a new set that is the union of the two arguments.


union set1 set2


set1 - first set (must be: series bitset)

set2 - second set (must be: series bitset)


/case - Use case-sensitive comparison

/skip - Treat the series as records of fixed size

size - The size argument. (must be: integer)


Returns all elements present within two blocks or strings ignoring the duplicates.

    lunch: [ham cheese bread carrot]
    dinner: [ham salad carrot rice]
    probe union lunch dinner
    [ham cheese bread carrot salad rice]

    probe sort union [1 3 2 4] [3 5 4 6]
    [1 2 3 4 5 6]

    string1: "CBDA"    ; A B C D scrambled
    string2: "EDCF"    ; C D E F scrambled
    probe sort union string1 string2

    items: [1 1 2 3 2 4 5 1 2]
    probe union items items  ; get unique set
    [1 2 3 4 5]

    str: "abcacbaabcca"
    probe union str str

To obtain a unique set (to remove duplicate values) you can use UNIQUE.

Note that performing this function over very large data sets can be CPU intensive.


difference - Return the difference of two data sets.
exclude - Return the first set less the second set.
intersect - Create a new value that is the intersection of the two arguments.

<Back | Index | Next>

Copyright 2004 REBOL Technologies