edit txt file but save previous data

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Adriele Rocha
Adriele Rocha on 1 Jul 2015
Commented: dpb on 2 Jul 2015
helo guys
I generated a table , wrote in a txt file, and when I run again my code I will choose other file, it will write a new table... I want add this table in that same txt file which was the information of first table.
I did this at the end of program;
fid=fopen('dataFULL.txt','a+');
writetable(T,'dataFULL.txt','Delimiter',',');
fclose(fid);
when I run my code twice in order to choose other file... it is rewriting my txt file and doesn't save the previous data :((((((((((
Guys... any idea how can I do this?

Accepted Answer

dpb
dpb on 1 Jul 2015
" If filename is the name of an existing text file, then writetable overwrites the file."
You can't with it. Since writetable opens the file using the file name and doesn't accept a file handle, the fopen in your code snippet above is totally ineffective; the two have nothing whatever in common with each other as far as what is written to the file; there are instead two totally independent file handles created/destroyed, the one explicitly is never used for anything.
Again as another question just a minute ago, seems like a reasonable enhancement request would be in order.
  2 Comments
Adriele Rocha
Adriele Rocha on 1 Jul 2015
you are right !!!Thanks
...The way of do that is just with fprintf, but fprintf doesn't accept cells as input. But I figured out a way :)
dpb
dpb on 2 Jul 2015
"_fprintf doesn't accept cells..."_
Yes, you must cast to char() or "use the curlies, Luke" to dereference the cell content to the underlying array values or strings.

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