I'm working a module with some accumulation/reduction/statistical formulas: average(iterable): stddev(iterable, sample=False) product(iterable) nlargest(iterable, n=1) nsmallest(iterable, n=1) The questions that have arisen so far are: * What to call the module * What else should be in it? * Is "sample" a good keyword to distinguish from population stddev? * There seems to be a speed/space choice on how to implement nlargest/nsmallest. The faster way lists out the entire iterable, heapifies it, and pops off the top n elements. The slower way is less memory intensive: build only a n-length heap and then just do a heapreplace when necessary. Note, heapq is used for both (I use operator.neg to swap between largest and smallest). * Is there a way to compute the standard deviation without multiple passes over the data (one to compute the mean and a second to sum the squares of the differences from the mean? Raymond Hettinger