[REBOL] Re: none? ???
From: joel:neely:fedex at: 19-Apr-2002 7:37
Hi, Richard,
Richard Coffre wrote:
> Hi,
>
> I got an input file like this :
>
> 100002 050042011006470
> 100002 050100000000000
> 100003 050042011006470
> 100004 050042011003653
> 100005 050042011004029
> 100006 050049750304500
> 100007 250042011006470
> 100007 250100000000000
> 100008 250042011003653
> 100009 250042011004029
> 100010 250049750304500
> 100011 060042011006470
>
> and the following code :
>
> tcs: [
> [ tcgrp01 "05" "06" "07" "15" "16" "17" "25" "26" "27" "35" "36" "37" ]
> [ tcgrp02 "02" ]
> ]
>
> texte: read/lines output
> offset: 7
>
> foreach ligne texte [
> foreach grp tcs [
> tc: remove/part copy/part ligne (offset + 2) offset ; Keep the two first characters
after the index and the extra space
> if not none? [ select grp tc ] [
> print rejoin [ tc "-" first grp ]
> ]
> ]
> ]
>
> In order to test if tc is included in the block. If so, it should print the first element
of the sub block.
>
> Currently, it always prints the first element. Why ?
>
There are at least three major flaws in the above code:
1) You are handing NONE? a *block* when you write
if not none? [ select grp tc ]
I suspect you confused square brackets with parentheses, but no
punctuation is needed at all. Since any block value (no matter
what contents) differs from NONE? , the test NOT NONE? [...]
always succeeds.
2) You have no exit from the inner loop after success, so the
subsequent groups within TCS will be tested even if after
finding the appropriate value (and -- based on the previous
comment -- you'll get bogus output from subsequent tests).
3) You are using SELECT instead of FIND. That will give you
an error if you are searching for e.g. "37" because SELECT
returns the value *following* the search target (and there's
nothing after "37", so you'll get NONE).
There are also the minor inefficiencies that:
1) You are extracting the tested substring on every pass through
the inner loop, even though it shouldn't change.
2) You are copying and then discarding the prefix instead of
just copying the part you need.
And a semantic confusion that OFFSET isn't actually the offset
into the string of the part of interest, it is the amount to
discard. If you're discarding 7 characters, then the portion
of interest begins at position 8 (thanks to the 1-origin mess).
Fixing those problems, and simulating your input by parsing
the sample string...
text: parse/all {100002 050042011006470
100002 050100000000000
100003 050042011006470
100004 050042011003653
100005 050042011004029
100006 050049750304500
100007 250042011006470
100007 250100000000000
100008 250042011003653
100009 250042011004029
100010 250049750304500
100011 060042011006470} "^/"
tcs: [
[
tcgrp01
"05" "06" "07" "15" "16" "17" "25" "26" "27" "35" "36" "37"
][
tcgrp02
"02"
]
]
inset: 8
foreach line text [
use [tc] [
tc: copy/part at line inset 2
foreach grp tcs [
if found? find grp tc [
print rejoin [ tc "-" first grp ]
break
]
]
]
]
We get this output:
05-tcgrp01
05-tcgrp01
05-tcgrp01
05-tcgrp01
05-tcgrp01
05-tcgrp01
25-tcgrp01
25-tcgrp01
25-tcgrp01
25-tcgrp01
25-tcgrp01
06-tcgrp01
Note that the sample data you supplied all fall within the
first group, however...
text: parse/all {100002 050042011006470
100002 010100000000000
100003 020042011006470
100004 030042011003653
100005 040042011004029
100006 050049750304500
100007 060042011006470
100007 070100000000000
100008 080042011003653
100009 090042011004029
100010 100049750304500
100011 110042011006470} "^/"
is a test data set that exercises both data groups and also your
do nothing if not found
case:
05-tcgrp01
02-tcgrp02
05-tcgrp01
06-tcgrp01
07-tcgrp01
Hope this helps!
-jn-
--
; Joel Neely joeldotneelyatfedexdotcom
REBOL [] do [ do func [s] [ foreach [a b] s [prin b] ] sort/skip
do function [s] [t] [ t: "" foreach [a b] s [repend t [b a]] t ] {
| e s m!zauafBpcvekexEohthjJakwLrngohOqrlryRnsctdtiub} 2 ]
