Question of begginer

victor79 · August 19, 2008, 11:57pm

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Message-ID: <763b8dd1-d05b-4761-bd2c-b7cc88f4d191@y38g2000hsy.googlegroups.com>
Subject: Question of begginer
From: victor79
To: “Kdb+ Personal Developers”
X-Google-Approved: simon.garland@gmail.com via email at 2008-08-20 14:43:07

I try understand expression:
ini:0:`test.ini
ini_tree:{r:(0 1) _ x; r[1]:{x[0]:(-1 _ x[0]); x}'{(0,1+x?“=”)
x}‘r[1]; r}’(&{~~((1+x?“[”) x)?“]”}'ini2) _ ini2:{x[&{~1>#x}'x]}[ini]
and convert it to K4. What means {…} without in &{~1>#x}'x ?
and can anybody help convert this exact as above only for K4? (this is
parser for ini file)

Aaron_Davies · August 21, 2008, 2:29am

On Wed, Aug 20, 2008 at 6:57 AM, victor79 wrote:

> I try understand expression:
> ini:0:`test.ini
> ini_tree:{r:(0 1) _ x; r[1]:{x[0]:(-1 _ x[0]); x}'{(0,1+x?“=”)
> x}‘r[1]; r}’(&{~~((1+x?“[”) x)?“]”}'ini2) _ ini2:{x[&{~1>#x}'x]}[ini]
> and convert it to K4. What means {…} without in &{~1>#x}'x ?
> and can anybody help convert this exact as above only for K4? (this is
> parser for ini file)

{} marks a function definition, regardless of how it’s later invoked.
in this case, it’s being invoked once for each x. (apostrophe is the
adverb “each”.)

what language is your sample in?
–
Aaron Davies
aaron.davies@gmail.com

Aaron_Davies · August 21, 2008, 2:36am

On Wed, Aug 20, 2008 at 6:57 AM, victor79 wrote:
>
>> I try understand expression:
>> ini:0:`test.ini
>> ini_tree:{r:(0 1) _ x; r[1]:{x[0]:(-1 _ x[0]); x}'{(0,1+x?“=”)
>> x}‘r[1]; r}’(&{~~((1+x?“[”) x)?“]”}'ini2) _ ini2:{x[&{~1>#x}'x]}[ini]
>> and convert it to K4. What means {…} without in &{~1>#x}'x ?
>> and can anybody help convert this exact as above only for K4? (this is
>> parser for ini file)
>
> {} marks a function definition, regardless of how it’s later invoked.
> in this case, it’s being invoked once for each x. (apostrophe is the
> adverb “each”.)
>
> what language is your sample in?

incidentally your code is perfectly fine k4, with just one bug: k4
parsing rules make it hard to put an underscore in a variable name.
(it’s interpreted as the “drop” operator.) change “ini_tree” to
“iniTree” and it will work fine.
–
Aaron Davies
aaron.davies@gmail.com

victor79 · August 21, 2008, 5:36am

User-Agent: G2/1.0X-Google-Token: Cyt3wAwAAADJp_f0bGuXmpd8TMSAGWYzX-HTTP-UserAgent: Mozilla/5.0 (Windows; U; Windows NT 5.1; ru; rv:1.8.1.16) Gecko/20080702 Firefox/2.0.0.16,gzip(gfe),gzip(gfe)Message-ID: Subject: Re: Question of begginerFrom: victor79 To: “Kdb+ Personal Developers” X-Google-Approved: simon.garland@gmail.com via email at 2008-08-21 06:11:50I have kdb+ 2.4 from code.kx.com. In this version don’t work previsionexpression.q){x[&{~1>#x}‘x}[(“as”;“qwe”;“a”)]’}q)k){x[&{~1>#x}‘x}[(“as”;“qwe”;“a”)]’}if get examples from http://en.wikipedia.org/wiki/K_(programming_language)its don’t evalutes in q) mode nor k). May be in 2.3 this work, but notin 2.4.(I don’t search version where it work, i simply study.)Prevision sample while wait, can you help me recognize `$‘’'$“asdf”(it work, but I don’t understand it. From http://www.nsl.com/k/kparse.k, second line)?

Aaron_Davies · August 21, 2008, 12:43pm

On Thu, Aug 21, 2008 at 12:36 PM, victor79 wrote:

> I have kdb+ 2.4 from code.kx.com. In this version don’t work prevision
> expression.

as i said, your ini parser is fine, except for the name of the
variable, which gives k4 problems q wouldn’t have

here’s the code running over my windows boot.ini (copied and renamed
as test.ini):

> cat test.ini
[boot loader]
timeout0
default=multi(0)disk(0)rdisk(0)partition(1)WINDOWS
[operating systems]
multi(0)disk(0)rdisk(0)partition(1)WINDOWS=“Microsoft Windows XP
Professional” /noexecute=optin /fastdetect
> q
KDB+ 2.4 2008.07.22 Copyright (C) 1993-2008 Kx Systems
l64/ 8(8)core 32135MB

q)k)ini:0:test.ini;iniTree:{r:(0 1) _ x; r[1]:{x[0]:(-1 _ x[0]); x}'{(0,1+x?"=") _x}'r[1]; r}'(&{~~((1+x?"[")_ x)?"]"}'ini2) _ ini2:{x[&{~1>#x}'x]}[ini] q)iniTree ,"[boot loader]" (("timeout";"30");("default";"multi(0)d.. "[operating systems]" "multi(0)disk(0)rdisk(0)partition(1)\W.. q)show each iniTree; ,"[boot loader]" (("timeout";"30");("default";"multi(0)disk(0)rdisk(0)partition(1)\WINDOWS")) "[operating systems]" "multi(0)disk(0)rdisk(0)partition(1)\WINDOWS" ""Microsoft Windows XP Professional" /noexecute=optin /fastdetect" > q){x[&{~1>#x}'x}[("as";"qwe";"a")] > '} > q)k){x[&{~1>#x}'x}[("as";"qwe";"a")] > '} yes, you'll note the unmatched left brace at the start of the expression. i think it's supposed to be k){x[&{~1>#x}'x]}[("as";"qwe";"a")]: q)k){x[&{~1>#x}'x]}[("as";"qwe";"a")] "as" "qwe" "a" > if get examples from http://en.wikipedia.org/wiki/K_(programming_language) > its don't evalutes in q) mode nor k). May be in 2.3 this work, but not > in 2.4. > (I don't search version where it work, i simply study.) i think that's mostly k3, some of them need a little translation. e.g. here's the prime tester over 3-100: q)k){y@&x'y}[{&/x .q.mod/:2_!x}]3_!100 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 73 79 83 89 97 (int!int was apparently mod in k3; in k4, it's a function written in k and defined in the file q.k) > Prevision sample while wait, can you help me recognize $‘’‘$“asdf”
> (it work, but I don’t understand it. From http://www.nsl.com/k/kparse.k
> , second line)?

bear in mind that i’m executing this in k4; i make no guarantees that
this is what this code would do in k3

i also have no idea what the point of this is, as i don’t understand
lines 5 or 6 of the file

sym cast of each each each string x (i.e.apply the first operation,
sym cast, to the fourth layer of a multi-layer structure)

setting S in k4 is

q)k)S:(nnn;vvv;nvn;nmn;mnv;vnavva) S is a general list containing syms and a list of syms (),/:S (join empty list to each S) is a trick for making an atom a list while leaving a list unchanged. it converts S to a list of list of sym (no more atomic elements) q)k)(),/:S ,nnn
,vvv ,nvn
,nmn ,mnv
vnavva

$S is string of S; it casts each sym item to a string, making S a list
of list of string

q)k)$(),/:S
,“nnn”
,“vvv”
,“nvn”
,“nmn”
,“mnv”
(“vna”;“vva”)

$ is cast to sym; the top layer of the structure is the thing itself; the second layer is the lists of string; the third layer is the individual strings in the lists; the fourth layer is the characters in the strings: $’‘’ applies the cast to the characters

q)k)$'''$(),/:S ,nnn
,vvv ,nvn
,nmn ,mnv
(vna;vva)
–
Aaron Davies
aaron.davies@gmail.com

victor79 · August 26, 2008, 5:57am

> you’ll note the unmatched left brace at the start of theexpressionyes, I see now>$S is string of Sin q not exists monadyc $, therefore I don’t understand, but learn Kdocumentation i understand,Thanks.

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