Insert String in a CSV file matlab - matlab

Question

how do I insert a string into a csv file in matlab. i used this code to write some data and create my csv file:
and here is the output of the code:
I'm trying to insert some text in the first 2 columns before the numerical data..
thanks in advance :)

Answer 1

There are several approaches are possible here.
Let's take a look at some of them:
If you need to add string to your csv file.
For example, I create some csv file like your:
q = [1 2 3 4 5 6 7];
csvwrite('csvlist4.csv',q,2,0);
All troubles is to add some string to csv - it's because we need to combine numeric and text data. There are no good functions for it in Matlab except low levels:
c = 'some big text';
fid = fopen('csvlist4.csv','r+');
fprintf(fid,c);
How it works: the data in csv is an array. I put data in 3rd row, so first and second is an empty but they have ','. When you use fprintf it will replace this , with your text. So if text is too long it will overwrite your data.
How to avoid this?
Easiest way - is to do it with help of xlswrite function. For your example:
txt = cell(size(Q))
txt{1} = 'this is your text'
X = [txt; num2cell(Q)]
xlswrite('new.xlsx',X)
Result:
Important moment here: number of cell for text must be the same as your data. But I filled with the text only first cell in my example.
And the one more way: read csv file, modify it's data and write to csv:
csvwrite('csvlist4.csv',a,2,0);
m = csvread('csvlist4.csv');
fid = fopen('csvlist4.csv','w');
c = 'your text'
fprintf(fid, c); fprintf(fid, '\n');
fclose(fid);
dlmwrite('csvlist4.csv', m(3:end,:), '-append');
Of course you can use cell array instead c and so on and so on.
Hope it helps!