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Re: Debracketing array symbols

  • To: mathgroup at smc.vnet.net
  • Subject: [mg92122] Re: [mg92079] Debracketing array symbols
  • From: Bob Hanlon <hanlonr at cox.net>
  • Date: Sat, 20 Sep 2008 05:01:49 -0400 (EDT)
  • Reply-to: hanlonr at cox.net

deBracket[x_] := 
 x /. A_Symbol[n__Integer] :> 
   ToExpression[
    StringJoin[Prepend[ToString /@ {n}, ToString[A]]]]

X[1] // deBracket

X1

{A[1], A[2], A[3], A[4]} // deBracket

{A1,A2,A3,A4}

{{W[1, 1], W[1, 2]}, {W[2, 1], W[2, 2]}} // deBracket

{{W11, W12}, {W21, W22}}


Bob Hanlon

---- carlos at Colorado.EDU wrote: 

=============
Hi,

For a class project I generate 1D and 2D arrays of arbitrary size with
entries <letters>[i] and <letters>[i,j] that I need then to convert
to <letter>i and <letter>ij for export to other languages that do not
allow brackets in symbol names. E.g.

1D:  {A[1],A[2],A[3],A[4]} -> {A1,A2,A3,A4}

2D:  {{W[1,1],W[1,2]},{W[2,1],W[2,2]}}  -> {{W11,W12},{W21,W22}}

Question: would this be the simplest way to do it?

DebracketArrayEntries[Wm_]:=Module[{dim,rep,i,j,n,m,s,Wr},
    rep={"["->"","]"->"",","->""," "->""}; Wr=Wm;
    dim=Length[Dimensions[Wm]];
    If [dim==1,n=Length[Wm]; Print["n=",n];
        For [i=1,i<=n,i++, s=ToString[Wm[[i]]];
             Wr=Wr/.Wm[[i]]->Symbol[StringReplace[s,rep]] ]];
    If [dim==2,{n,m}=Dimensions[Wm];
        For [i=1,i<=n,i++, For[j=1,j<=m,j++, s=ToString[Wm[[i,j]]];
             Wr=Wr/.Wm[[i,j]]->Symbol[StringReplace[s,rep]] ]]];
    Return[Wr]];

The procedural style is to simplify conversion to C++.


--

Bob Hanlon



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