Creating a text file to specific format

Hi,

I have a matrix called data (3652500 x 3). But data matrix dont have the header (i.e. names).

I want to insert column headers as shown below and write the output to a text file inserting 4th column from another matrix called output (3652500 x 1). I need to insert the output matrix in the 4th column of data matrix with 3 spaces between 3rd columns and 4th column. (See the header and sample rows below)

DATE TMAX TMIN RAIN
3000001 -99.9 -99.9   0.6
3000002 -99.9 -99.9   0.5

How can I do it MATLAB.

Any help is appreciated.

Thanks.

Answer 1

[Image Analyst]

With fprintf() you can make it look anyway you want. Have you tried that function?

output = 99*rand(10,4);
output(:,1) = round(output(:,1))
filename = 'deleteme.txt';
fid = fopen(filename, 'wt');
if fid ~= -1
  fprintf(fid, 'DATE TMAX TMIN RAIN\n');
  for row = 1 : size(output, 1)
      fprintf(fid, '%d %.1f %.1f   %.1f\n', output(row, :));
  end
  fclose(fid);
end

[Damith]

I haven't tried that.

Where should my data matrix go in your code.? I need to create a text file. What values will it fill for 1, 2, and 3 columns.?

Thanks.

[Image Analyst]

I forgot to put the fid inside the fprintf(), and 'wt' inside fopen(). It's correct now.

[Damith]

Hi,

Thanks a lot for your code. It's working now but one more problem is as shown in the sample output is that I need to right justify the output so that decimal points are aligned properly.

Can you please suggest me a method in your code.

3792227 -99.9 -99.9   1.1
3792228 -99.9 -99.9   13.9
3792229 -99.9 -99.9   0.1
3792230 -99.9 -99.9   12.4

I need my output to appear as

3792227 -99.9 -99.9   1.1
3792228 -99.9 -99.9  13.9
3792229 -99.9 -99.9   0.1
3792230 -99.9 -99.9  12.4

Many thanks again.

[Image Analyst]

It's just like any format string that you're used to in most any other language that you've ever used. If you use %.1f, the field width varies according to the size of the number. If you put %6.1f, it will pad out to make it a fixed field width of 6 characters.

[Damith]

Thanks. I figured it out.