robot4_motors.txt
M 204 20795 20795 3000 0 16067 16066 3000 0 0 0 6000 0
M 524 20795 20794 3000 0 16067 16066 3000 0 0 0 6000 0
M 735 20795 20795 3000 0 16067 16066 3000 0 0 0 6000 0
M 995 20795 20795 3000 0 16067 16067 3000 0 0 0 6000 0
M 995 20795 20795 3000 0 16067 16067 3000 0 0 0 6000 0
M 1233 20795 20795 3000 0 16067 16067 3000 0 0 0 6000 0
M 1499 20795 20795 3000 0 16067 16067 3000 0 0 0 6000 0
M 1763 20795 20795 3000 0 16067 16067 3000 0 0 0 6000 0
This is a data file. I want to take out 3rd column and 7th column from the file and plot them as well. I write down the code in matlab.
Code
f = fopen('robot4_motors.txt');
plot(f(:, 3), f(:, 7))
But the code did not work .
Throws error Index in position 2 exceeds array bounds (must not exceed 1).
Error in trick1 (line 21) plot(f(:, 3), f(:, 7))
fopen returns a numeric id which refers to the opened file, it's not a matrix. You need to parse the file to extract the data.
One way to parse the file is to use dlmread since this is a space delimited file.
% Read data into M starting at row 0, column 1.
M = dlmread('robot4_motors.txt', ' ', 0, 1);
After this, M will contain all the entries from the file except the first column (which aren't numeric).
>> M
M =
204 20795 20795 3000 0 16067 16066 3000 0 0 0 6000 0
524 20795 20794 3000 0 16067 16066 3000 0 0 0 6000 0
735 20795 20795 3000 0 16067 16066 3000 0 0 0 6000 0
995 20795 20795 3000 0 16067 16067 3000 0 0 0 6000 0
995 20795 20795 3000 0 16067 16067 3000 0 0 0 6000 0
1233 20795 20795 3000 0 16067 16067 3000 0 0 0 6000 0
1499 20795 20795 3000 0 16067 16067 3000 0 0 0 6000 0
1763 20795 20795 3000 0 16067 16067 3000 0 0 0 6000 0