Calling all functional programming fans... is Python's built-in reduce() a left-fold or a right-fold?
Wikipedia says it's a left-fold: http://en.wikipedia.org/wiki/Fold_(higher-order_function) but other people say it's a right-fold, e.g.: "... there is a `foldr` in Haskell that just works like `reduce()`" http://mail.python.org/pipermail/python-list/2007-November/638647.html and "Note that Python already has a variation of foldr, called reduce." http://blog.sigfpe.com/2008/02/purely-functional-recursive-types-in.html So which is correct? Or is it that different people have different definitions of foldl() and foldr()? -- Steven -- http://mail.python.org/mailman/listinfo/python-list
