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From: news@usc.edu
Newsgroups: comp.lang.apl
Subject: Re: Dyalog question
Message-ID: <11930@chaph.usc.edu>
Date: 12 Sep 90 01:21:07 GMT
References: <7273@umd5.umd.edu>
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In-reply-to: jph@suns.UMD.EDU's message of 11 Sep 90 07:00:01 GMT
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In article <7273@umd5.umd.edu> jph@suns.UMD.EDU (J. Patrick
Harrington) writes:

   Thanks  for the replies - I'm glad to see there are a few  Dyalog 
   users  on the net,  and that I was not overlooking something much 
   simpler. ... 

     Z <- UR NAME;R;N;J;I
   [1]  'unixfiles'[]SH'unixfiles' 'open' 'tread' 'close'
   [2]  'xutils'[]SH'xutils' 'ss'
   [3]  R <- 2 tread (N <- open NAME) 10000 & close N
   [4]  J <- 1 cel dc shape execute ss(ss(ss(dc R[1])'-' '@')'e' 'E')'+' ''
   [5]  N <- dc shape R & Z <- N J reshape 0 & I <- 1
   [6]  ONE: Z[I;] <- execute ss(ss(ss(I pick R)'-' '@')'e' 'E')'+' ''
   [7]  ->(N ge I <- I+1)/ONE

     where   dc=disclose,   @=high  minus,   ge=greater  or   equal, 
   &=diamond,  and cel=ceiling.  Line [5] looks at the first row  to 
   find  the  number of columns in the file. 
      Still,  it  would be nice to have  something  "smarter",  that 
   would  fill short rows with zeros,  discard non-numeric comments, 
   etc.  

First off, I'm not a Dyalog user, so maybe I should just shut up...

However, normally, the way you 'fill short rows with zeros' is with an
overtake.  e.g. on line [6] 
                            ONE: Z[I;] <- J take execute ....

As for discarding non-numeric comments, well.. that depends on what a
comment is, but try:

[5.5]        B <-     J reshape 0
[6]   ONE:   T <-     ss(ss(ss(I pick R)'-' '@')'e' 'E')'+' ''
[6.1]     ->(~ v/  '0123456789'   element_of T)/NEXT
[6.2]     ->(~ ^/ T element_of '@0123456789E ')/NEXT
[6.3]        B[I ] <- 1
[6.4]        Z[I;] <- J take execute T
[7]   NEXT:  I <-     I + 1
[8]       ->(N ge I)/ONE
[9]          Z <-     B /[1] Z


note that element_of is the old familiar epsilon, and that
~ v/ may be done more quickly as ~ 1 element_of, and that
~ ^/ may be done more quickly as   0 element_of

'nuf said