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Re: WriteList function?

  • To: mathgroup at smc.vnet.net
  • Subject: [mg9329] Re: [mg9320] WriteList function?
  • From: jpk at max.mpae.gwdg.de
  • Date: Sat, 1 Nov 1997 03:33:18 -0500
  • Sender: owner-wri-mathgroup at wolfram.com

Hi Tom,


with the definitions


writeList[stream_,l_List,numsep_String]:=
  Write[stream,Infix[l,numsep]]


writeMatrix[stream_,mat_?MatrixQ,numsep_:" "]:=
  Scan[writeList[stream,#,numsep]&,mat]


You can say

writeMatrix["stdout",{{1,2,0.5,0.8},
		      {7,1,2,4},
		      {0.5,1,1,2}}," "]


to get the matrix on screen in the way You want. And You can send it on
a open stream in this way by replacing the first argument of 
writeMatrix[] with a open output stream.

Hope that helps
  Jens

> Hi, I am a new Mathematica user.  
> 
> I have had success reading files of space-separated numbers using
> ReadList, but now need to output my results in the same fashion. i.e.
> one row of the matrix should appear on one text line, 
>      no commas, nor curly braces are desired in the output.
> 
> I have searched the manual for a corresponding WriteList function
> without success.
> 
> Any suggestions?   I may have to resort to awk/sed/perl to  postprocess
> the file, but I would've thought Mathematica would've provided the
> facilities to write data in a general format.
> 
> Thank you kindly,   --tom thomas
> -------------------------------------------------------------------
> example:
> In[1]:= !! /tmp/mymat
> 1 2 3 
> 4 5 6
> 7 8 9
> 
> In[1]:= mydata =  ReadList["/tmp/mymat", Number, RecordLists->True]
> 
> Out[1]= {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}}
> 
> In[2]:= stmp = OpenWrite["/tmp/myoutput"]
> 
> Out[2]= OutputStream[/tmp/myoutput, 4]
> 
> In[3]:= Write[stmp, mydata]
> 
> 
> %cat /tmp/myoutput 		
> {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}}
> 
> I need to see instead:
> 1 2 3 
> 4 5 6
> 7 8 9
> 


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