matrix concatenation

I need to create a text file with 3 columns. first two columns are of the same size, 100. The 3rd column just has one number in it. How can I do that?

Answer 1

[Walter Roberson]

With col1, col2, and col3 being column vectors:

fmt = ['%f %f %f\n' repmat('%f %f\n', 1, 99)];
fid = fopen('YourOutputFile.txt', 'wt');
fprintf(fid, fmt, col1(1), col2(1), col3(1), [col1(2:end), col2(2:end)].');
fclose(fid);

Warning: the details of the fprintf() call depend upon col1 and col2 being column vectors!

[Baba]

getting an error in 3rd line of your code

I created col3, as col3=[1]

set first two column vectors to col1 and col2

[Baba]

and the txt file is saved as blank

[Walter Roberson]

Sorry, dropped an important parameter. I have edited it in to the above.

[Baba]

Perfect thank you!

Answer 2

[Sean de Wolski]

Do you want the third column to have 100 values the same?

If so:

A = [c1,c2,repmat(c3,100,1)];

If not:

A = [{c1} {c2} {c3}]

for more info:

doc cell

[Baba]

yep, 3rd column should only have 1 value in it. I'm having trouble writing A to a txt file using a dlmwrite command.

[Baba]

that one value should not repeat, just appear in the first row.

[Walter Roberson]

In order to do it with dlmwrite(), you would have to make two dlmwrite() calls, with the second using the -append option.