How to plot specific data from a imported matrix?

Good day all,

Maybe some basic stuff, but I need support on following situation:

I used [data] = xlsread('testfile.xlsx') to import data from excel in order to create a matrix. See image.

Now I would like to plot the data into a 2D-diagram. So x will the first column and y the second column. How can I separately plot for example the data from row 2 to 5 into a diagram. Many thanks for your support.

Answer 1

[Dave B]

You can plot all data with a line plot using

plot(data(:,1),data(:,2))

You can plot all data with a scatter plot using

scatter(data(:,1),data(:,2))

You can make a line plot of rows 2 to 5

plot(data(2:5,1),data(2:5,2))

or scatter:

scatter(data(2:5,1),data(2:5,2))

Note: xlsread is not recommended. The documentaiton recommends using readtable, readmatrix, or readcell instead.

For more on indexing into arrays:

https://www.mathworks.com/help/matlab/math/array-indexing.html

For more types of plots:

https://www.mathworks.com/help/matlab/2-and-3d-plots.html

[Hans Lipton]

Thanks, Dave. This helps a lot!

[Hans Lipton]

Is there any possiblity to remove the brackets?

[Dave B]

This is a MATLAB data type known as a cell array, it's a sort-of old fashioned way to store text. Note that the brackets aren't really part of the text, they're just indicating the way the data are stored (and how you'd access it).

Either way, strings are way better than cells (IMO) and the brackets disappear when you use strings. You can convert after reading it in:

T.Name = string(T.Name)

Or read in those chars directly as a strings:

T = readtable(yourfile, 'TextType', 'string')

[Hans Lipton]

Many thanks again, this a very helpful support.