[REBOL] Re: Select VS path access
From: janko:mind-nest at: 9-Nov-2002 20:41
Hi all!
> RMM> Hi, is there a difference (speed?) between the following two methods?
I made the folowing...
b: [ a "leter a" b "leter b" c "leter c" d "leter d" ]
a: func [ x ][ start: now/time/precise loop 100000 [ do x ] print
now/time/precise - start ]
and then tested with (>> is from rebol console)
>> a "b/d"
0:00:01.1
>> a "b/a"
0:00:00.99
>> a "select b 'd"
0:00:01.1
>> a "select b 'a"
0:00:00.99
You can see that in hundred thousand repetitons select and path spend
exactly same time
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There is one difference betwen this two, that I know off.
if you have block like
a: [ "a" "leter a" "b" "leter b" ]
you cant use path
>> print a/"a"
** Syntax Error: Invalid path -- a/
>> print a/a
** Script Error: Invalid path value: a
but you can use select...
>>print select a "a"
leter a
This is often used in rebol databases where you use select to retrieve the
record by the key.
[
....
key002
[ "ksadfk" "dfkasdf" "adfa"]
key003
[ "dfkasdf" "adfa" "ksadfk"]
.....
]
I hope this helped!
:janko
url: [ http://www.mind-nest.com ]
