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Re: Export with append??

• To: mathgroup at smc.vnet.net
• Subject: [mg129484] Re: Export with append??
• From: Szabolcs <szhorvat at gmail.com>
• Date: Wed, 16 Jan 2013 23:16:53 -0500 (EST)
• Delivered-to: l-mathgroup@mail-archive0.wolfram.com
• Delivered-to: l-mathgroup@wolfram.com
• Delivered-to: mathgroup-newout@smc.vnet.net
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• References: <kd5hu2$jjp$1@smc.vnet.net>

Hello Maarten,

In fact there is a simple way to make Export append rather than overwrite.  Please see here:

http://mathematica.stackexchange.com/a/2228/12

You just need to use a stream in place of the file name:

file = OpenAppend["out.txt"]

Export[file, data, "CSV"];
WriteString[file, "\n"];

Close[file]

On Wednesday, 16 January 2013 01:38:58 UTC-5, Maarten van der Burgt  wrote:
> Dear Alexei,
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> Thanks for your help. Hope the Wolfram folks are reading this as well.
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> Something simple like this should really be an option in the function
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> Export.
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> Meanwhile I found back something similar for XLS files in my knowledge
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> base:
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> XLAppend[oldfile_, newfile_, newdata_] :=  Module[
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> {sheets, olddata, completedata},
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>   sheets = Import[oldfile, "Sheets"];
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>   olddata = {#, Import[oldfile, {"Sheets", #}]} & /@ sheets;
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>   completedata = Join[olddata, newdata];
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> Export[newfile, Rule @@@ completedata]
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> ]
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> Best regards,
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> Maarten
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> Maarten van der Burgt
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> Product Engineering  - ICOS Division
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> ________________________________
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> 
> KLA-Tencor | ICOS Division
> 
> Tel: +32 16 398220 | Direct: +32 16 398263 | Fax: +32 16 400067
> 
> 
> 
> KLA-TENCOR (Belgium) - Haasrode Research Park 1112 - Esperantolaan 8 -
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> B-3001 Leuven - BELGIUM
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> 
> Mail: maarten.vanderburgt at kla-tencor.com
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> From: Alexei Boulbitch [mailto:Alexei.Boulbitch at iee.lu]
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> Sent: maandag 14 januari 2013 10:22
> 
> Cc: Maarten van der Burgt
> 
> Subject: Re: Export with append??
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> Hallo,
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> With a command like
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> Export["myfile.dat", results, "List" ]
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> is there a way to append the results to an existing myfile.dat, rather
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> than creating or overwriting an existing file?
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> thanks for your help,
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> Maarten
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> Hi, Maarten,
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> A simple workaround is to import your file, append a new file to it and
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> then - to export the combined list. Assume that your mathematica
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> notebook entitled "trialImportExport.nb"  is situated in the same folder
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> as the already existing list entitled "myfile.dat".
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> To be precise I generated the file myfile.dat with the list:
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> {25, 36, 49}
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> in it. Assume further that I want to append the list
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> {a,b,c}
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> to it. Then the code
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> lst1=Import[NotebookDirectory[]<>"myfile.dat"]//Flatten;
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> lst2={a,b,c};
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> lst3=Append[lst1,lst2]//Flatten;
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> Export[NotebookDirectory[]<>"myfileNew.dat",lst3]
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> Does the job. The output cell below:
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> D:\Documents and Settings\ABo\My
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> Documents\Works\Mathematica_works\Examples\TrialFiles\myfileNew.dat
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> shows that the file has been successfully exported.
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> I intentionally gave the resulting file a new name, "myfileNew.dat", to
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> check the result, but the old name can also be given to it.
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> Have fun, Alexei
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> Alexei BOULBITCH, Dr., habil.
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> IEE S.A.
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> ZAE Weiergewan,
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> 11, rue Edmond Reuter,
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> L-5326 Contern, LUXEMBOURG
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> Office phone :  +352-2454-2566
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> Office fax:       +352-2454-3566
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> mobile phone:  +49 151 52 40 66 44
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> e-mail: alexei.boulbitch at iee.lu

• Follow-Ups:
  • Re: Export with append??
    • From: Szabolcs HorvÃt <szhorvat@gmail.com>
  • Re: Export with append??
    • From: Murray Eisenberg <murray@math.umass.edu>