>>> a = (([1],[2],[3,31,32],[4]), ([5],[6],[7, 71, 72]), ([8],[9])) >>> reduce(operator.add, a) # it makes a long list now ([1], [2], [3, 31, 32], [4], [5], [6], [7, 71, 72], [8], [9])
When I make list comprehension, the list hierarchy is allways the same or >>> [item for item in a] # the deepnes is the same [([1], [2], [3, 31, 32], [4]), ([5], [6], [7, 71, 72]), ([8], [9])] >>> [(item, item) for item in a] # it is deeper with one level You are not using operator add anywhere in there. So you won't reduce anything! But reduce is tricky to reproduce using comprehensions because it involves combining two elements using an operation. And one of the elements is the running result. So count = 0 [count + item for item in alist] won't work because we never change count - and assignments aren't allowed inside a comprehension. There may be a clever way of doing it but I can't think of it and certainly not a way that would be as readable as reduce()! Do you have any particular need to avoid reduce? Or is it just curiosity? Alan g _______________________________________________ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
