Set X,y,z Values From Text File Into Separate Arrays

I have been trying to find out how to do this for days now, so I am finally asking how. I am newish to programming. Here is my problem.

I am trying to extract x,y,z coordinates from a text file arranged as such:

x,y,z
x,y,z
x,y,z
etc.

I need to be able to extract the x column into an array, the y into an array, and the z into an array. I learned how to pull it into a string, and how to split for every line, but i don't know how to split after each comma and separate them.