Matrices from Data in Workspace

Hi, I'm extracting data from the graph I've plotted and export the value into the workspace. I have around 238 values and I need to do matrices based on the values. How do I do the matrices based on the values I've obtained in the workspace other than rewrite it back one by one? Because I dont think it will be practical to rewrite the numbers one by one as I might messed up the value.