As the post title describes, I have two data sets and want to multiply them together (and finally plot them). The problem I have is that the data are different length, so for example using Matlab: >>> data_set1 .* data_set2 But this would not give me the correct answer for a number of reasons. The data share the same x-axis (energy in MeV). The trouble is the first data starts around 0 MeV and ends around 11. The second data starts just before the end of the first data and extends further on. The region in which they overlap is the part I am interested. Another issue I have is the length between data points is non-uniform in both data sets. Is there a process to normalise or do something with the data to make them 'compatible'? For tools, I am using anything I can get my hands on. Excel for basic ideas, Python (Numpy and MatplotLib) for proper data analysis. I am fairly comfortable with Matlab but I don't have it where I work now (I can however download Octave).