Why is my "plot" function not working?

T = readtable('ELG3155_LAB3_part2_M_2V.xlsx', 'PreserveVariableNames', true);

x = T.("Time (ms)");

y = T.("Raw speed (mrad/s)");

grid on;

plot(x,y);

When i run this it says there is an error with my plot function, why?

[Matt J]

We can't run the code (because it's an image and because the data hasn't been provided)

[William]

@Matt J there, sorry.

Answer 1

[Star Strider]

Use the str2double function on the last four variables.

EDIT — (26 Mar 2023 at 10:28)

T = readtable('https://www.mathworks.com/matlabcentral/answers/uploaded_files/1336464/ELG3155_LAB3_part2_M_2V.xlsx', 'VariableNamingRule','preserve');
VN = T.Properties.VariableNames;
x = T.("Time (ms)");
y = str2double(T.("Raw speed (mrad/s)"));

figure
plot(x,y)
xlabel(VN{1})
ylabel(VN{3})
grid on

.

[William]

Thank you :)

[Star Strider]

As always, my pleasure!

Answer 2

[Walter Roberson]

The first row has time 00. That is text not numeric.

Looking at the left justification it looks to me as if the second column is text rather than numeric.

[Walter Roberson]

I checked in Excel itself, and sure enough, the 00 gives a warning about "Number stored as text", and all of columns 2, 3, 4 report the same thing.

If you use readmatrix() then everything will be converted to numeric.

Note: with default options, the 00 0 0 0 row will be detected as being header and will be skipped.