On Thu, Aug 27, 2009 at 9:23 AM, Vincent Schut<sc...@sarvision.nl> wrote: > Tim Michelsen wrote: >> Hello, >> I need some advice on histograms. >> If I interpret the documentation [1, 2] for numpy.histogram correctly, the >> result of the function is a count of the occurences sorted into each bin. >> >> (n, bins) = numpy.histogram(v, bins=50, normed=1) >> >> But how can I apply another function on these values stacked in each bin? >> Like summing them up or building averages? > > Hi Tim, > > If you just want to sum and/or average (= sum / count), you can shortcut > this using the weights parameter of numpy.histogram, e.g. something like: > > data = numpy.random.random((100,)) > countsPerBin = numpy.histogram(data) > sumsPerBin = numpy.histogram(data, weights=data) > averagePerBin = sumsPerBin / countsPerBin > > Regards, > Vincent.
Thanks for the pointer, I didn't realize that histogram also has a weights argument. It would be interesting to know what the overhead is for repeated calls to histogram for larger arrays, if anyone knows. Josef > >> >> Thanks, >> Timmie >> >> [1] http://docs.scipy.org/doc/numpy/reference/generated/numpy.histogram.html >> [2] >> http://www.scipy.org/Tentative_NumPy_Tutorial#head-aa75ec76530ff51a2e98071adb7224a4b793519e > > _______________________________________________ > NumPy-Discussion mailing list > NumPy-Discussion@scipy.org > http://mail.scipy.org/mailman/listinfo/numpy-discussion > _______________________________________________ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
