> tsort1=:] {&.>~ [: < [: tgrade [
I'd prefer
tsort1=: <@[EMAIL PROTECTED] {&.> ]
because it avoids slinging the left and right arguments
back and forth.
----- Original Message -----
From: "Sherlock, Ric" <[EMAIL PROTECTED]>
Date: Thursday, September 27, 2007 19:12
Subject: RE: [Jprogramming] /. in inverted tables
To: Programming forum <[email protected]>
> tsort1=:] {&.>~ [: < [: tgrade [
> ..is also useful. Sorts inverted table y by inverted table x
> (subset of
> columns of y)
> ,.each key tsort1 invtble
> ,.each tsort1~ tfreqtble key NB. Equivalent of tsort
> ,.each (tnub key) tsort1 tfreqtble key
>
> Oh and x0 defined in the previous post would be better defined as
> follows:
> x0=: 'ID',"1 ];._1 ' ',": 10000+ i.40
>
> --Sherlock, Ric wrote:
> > I'm investigating working with data stored in inverted tables.
> > <http://www.jsoftware.com/jwiki/Essays/Inverted_Table>
> >
> > Some example data:
> > hdr=: ;: 'ID DOB Sex Nat Height Weight Arrests'
> > x0=: 'ID',"1 ];._1 ' ',": 10000+ 40 [EMAIL PROTECTED] 4
> > x1=: 1998+ 40 [EMAIL PROTECTED] 4
> > x2=: (40 [EMAIL PROTECTED] 2){ >'Female';'Male'
> > x3=: (40 [EMAIL PROTECTED] 3){ >'NZ';'US';'CH'
> > x4=: 1.2 + 1 * ([EMAIL PROTECTED] 0)
> > x5=: 60 + 12 * ([EMAIL PROTECTED] 0)
> > x6=: 40 [EMAIL PROTECTED] 6
> > invtble=: x0;x1;x2;x3;x4;x5;x6
> >
> > I came up with the following to give the frequency of each
> > unique rows in an inverted table:
> > tfreq=: #/.~@:|:@:(i.&>)~
> >
> > key=: 1 3 2{invtble
> > ,.each tfreq key
> >
> > The following verb makes a frequency table:
> > tfreqtble=: [: tsort tnub , <@:tfreq
> >
> > ,.each tfreqtble key
> >
> > Or a more generalised version
> > tkeytble=: [: tsort ([: tnub [) , [: boxopen ]
> >
> > ,.each key tkeytble tfreq key
> >
> > And I can calculate say the sums of data columns by the set
> > of key columns e.g.
> > tkeysum=: ] +//.&.>~ <@:tindexof~@:[
> >
> > dat=: 4 5 6{invtble
> > ,.each key tkeysum dat
> >
> > But what I think I really want is a verb tkey, that does what
> > /. does, but on inverted tables.
> > Then instead of defining tkeysum, tkeymin, tkeymax ..., I
> > could do this:
> > key +/tkey dat
> > key <./tkey dat
> > key >./tkey dat
> > ...
> > Or in a sorted table:
> > ,.each key tkeytble key +/tkey dat
> >
> > Any pointers or other approaches to consider gratefully accepted!
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