On Thursday 16 June 2016 17:28, meInvent bbird wrote: > is there like c# have concurrent list ?
What is a concurrent list? Can you link to the C# documentation for this? To me, "concurrent" describes a style of execution flow, and "list" describes a data structure. I am struggling to understand what "concurrent list" means. > i find something these, but how can it pass an initlist list variable initlist = ['a', 'b', 'c'] result = comb(n, initlist) # pass initlist > is it doing the same function as itertools.combinations ? It is calling itertools.combinations. So, yes, it is doing the same function as itertools.combinations. > def comb(n, initlist): # the argument n is the number of items to select > res = list(itertools.combinations(initlist, n)) # create a list from the > # iterator > return res This does not generate the combinations in parallel. It generates them one at a time, and then creates a list of them. This is an interesting question. Somebody could probably write a parallel version of combinations. But I don't know that it would be very useful -- the limiting factor on combinations is more likely to be memory, not time. Suppose you generate combinations of 100 items, taken 10 at a time. If I remember the formula for combinations correctly, the total number of combinations is: 100!/(10! * 90!) = 17310309456440 combinations in total. If each generated combination took just *one* byte of memory, that would require over 17 TB of RAM. -- Steve -- https://mail.python.org/mailman/listinfo/python-list
