In Matlab, the colon operator describes a range between the two values n and m of a container.
For example, given a vector x = {4,2,67,2,5,26}, the following expression takes the values 3 through 6 and saves them in the vector y:
y = x(3:6)
resulting in the following values for y:
67 2 5 26
Another use of it is to index all elements of one dimension of a matrix:
x = rand(5,5)
x(:,1) = 1
would fill the first column of the matrix m with the following:
1.0000 0.9649 0.8003 0.9595 0.6787
1.0000 0.1576 0.1419 0.6557 0.7577
1.0000 0.9706 0.4218 0.0357 0.7431
1.0000 0.9572 0.9157 0.8491 0.3922
1.0000 0.4854 0.7922 0.9340 0.6555
Heres a simplified version of your plotting function:
plot(m(1,[1:3 1]),'*', 'Color',[0 0 0])
which plots values 1 to 3 of the first row of x and afterwards the first value (indicated by the space in the square brackets)
The output plot looks like this:
![plot(m(1,[1:3 1]),'*', 'Color',[0 0 0])](https://www.lemona.fr/i.sstatic.net/MZq6P.png)
changing the plot to
plot(x(1,[3:4 1]),'*')
(discarding the coloring here for better comparison)
would plot the values at index 3 and 4 with the additional value at index 1 like this:
As for the import in python, you might have to use "range" as described in this post:
Python Equivalent of MATLAB's colon operator
I hope this helps,
cheers,
Simon
