[REBOL] Re: Exclude Problems
From: joel:neely:fedex at: 28-Sep-2001 1:52
Hi, Ammon, and all,
I've been way busy with a pending s/w release, so haven't been
keeping up with this thread very well, but...
Ammon Cooke wrote:
> Sorry, I forgot to fully omptimize that code here is a lot
> smaller version:
>
> excl-only: func [
> "This is the Exclude function that doesn't exclude duplicates"
> block1 "The original block"
> block2 "The block to be 'excluded'"
> ][
> tmp-block: copy block1
> repeat val block2 [remove find tmp-block val]
> either not none? tmp-block[
> return head tmp-block
> ][
> return tmp-block
> ]
> ]
>
I'd suggest making TMP-BLOCK a /LOCAL to prevent contaminating
the global namespace.
I'm not clear on why the following wouldn't be a valid solution.
Am I missing some subtlety?
remove-all: func [source [block!] targets [block!] /local result] [
result: copy source
foreach target targets [
remove find result target
]
result
]
>> remove-all [1 2 3 4 5 6 7 8 9] [2 4 6 8]
== [1 3 5 7 9]
>> remove-all [9 8 7 6 5 4 3 2 1] [2 4 6 8]
== [9 7 5 3 1]
>> remove-all [1 9 2 8 3 7 4 5 6] [0 2 4 6 8]
== [1 9 3 7 5]
>> remove-all [1 9 2 8 3 7 4 5 6] []
== [1 9 2 8 3 7 4 5 6]
>> remove-all [1 2 2 3 3 3 4 4 4 4 5 5 5 5 5 6 6 6 6 6 6] [1 2 3 4 5 6 7 8 9]
== [2 3 3 4 4 4 5 5 5 5 6 6 6 6 6]
>> remove-all [] [1]
== []
>> remove-all [2] [1]
== [2]
>> remove-all [2] []
== [2]
>> remove-all [2] [2 2 2 2]
== []
>> remove-all [1 2 2 3 3 3 4 4 4 4 5 5 5 5 5 6 6 6 6 6 6] [9 8 7 6 5 4 3 2 1]
== [2 3 3 4 4 4 5 5 5 5 6 6 6 6 6]
I can't think of any more obvious test scenarios at the moment,
but would be happy to hear of anything I've overlooked.
-jn-
--
That so few now dare to be eccentric marks the chief danger of the
time.
-- John Stuart Mill (1806-1873)
FIX&PUNCTUATION&joel&dot&neely&at&fedex&dot&com
