How to use fwrite with a format subject to change

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012786534 2020-12-7

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评论： 012786534 2020-12-7

Hi,

I have a basic question: I am doing multiple SQL queries and exporting the result to text files. I want to use fwrite to export the data but the number of variables and the data types are liable to change between queries. How could I build a script sufficiently flexible to handle that ?

var_a = {'T1','T1','T1','T1'}';
var_b = [2,2,2,2]';
var_c = {'A','A','A','A'}';
var_d = [8.12,7.67,5.90,3.81]';
t = table(var_a, var_b, var_c, var_d)
file_format = ['%s %d %s %f\n'];
y = table2cell(t).';
fid = fopen('test.txt', 'wt');          
fprintf(fid, file_format, y{:});
fclose(fid);

Thank you,

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Answer 1

Steven Lord 2020-12-7

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https://ww2.mathworks.cn/matlabcentral/answers/684803-how-to-use-fwrite-with-a-format-subject-to-change#answer_568128

Since you're already storing your data in a table array, why not just use writetable?

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012786534 2020-12-7

Because things like writetable and writecell are really slow and fwrite is much faster. This matters depending on the number of SQL queries and the size of the files

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