How do I append data to an existing csv file using dlmwrite?

Hello! I have a csv that contains historical data. I want to append new data to that file each day so the file stays up to date. I have tried using dlmwrite to do this, but I keep getting the error that I have too many output arguements. Below is my code. Any help would be greatly appreciated!

sp_final = dlmwrite('spx_historical.csv',sp_new,'-append')

Answer 1

[Stephen23]

According to the dlmwrite documentation, the function does not have any outputs. So instead of calling this:

sp_final = dlmwrite('spx_historical.csv',sp_new,'-append')

You should call this:

dlmwrite('spx_historical.csv',sp_new,'-append')