marcstuart wrote: > How do I divide a list into a set group of sublist's- if the list is > not evenly dividable ? > consider this example: > > x = [1,2,3,4,5,6,7,8,9,10] > y = 3 # number of lists I want to break x into > z = y/x > > > what I would like to get is 3 sublists > > print z[0] = [1,2,3] > print z[2] = [4,5,6] > print z[3] = [7,8,9,10] > > obviously not even, one list will have 4 elements, the other 2 will > have 3., > the overriding logic, is that I will get 3 lists and find a way for > python to try to break it evenly, if not one list can have a greater > amount of elements > > Would I use itertools ? How would I do this ? > > Thanks >
Calculate the size of a normal sublist, and the amount of extra that goes with the last sublist. Then extract y-1 normal sized sublists and one possibly larger sublist. >>> x = [1,2,3,4,5,6,7,8,9,10] >>> y = 3 >>> s = len(x)/y >>> s # size of normal sublists 3 >>> e = len(x) - y*s # extra elements for last sublist >>> e 1 >>> z = [x[s*i:s*i+s] for i in range(y-1)] + [x[-s-e:]] #extract y-1 normal + 1 larger sublists >>> z [[1, 2, 3], [4, 5, 6], [7, 8, 9, 10]] Done! Gary Herron -- http://mail.python.org/mailman/listinfo/python-list
