Op 2009-05-26, Arnaud Delobelle schreef <arno...@googlemail.com>: > Sumitava Mukherjee <sm...@cognobytes.com> writes: > >> On May 26, 11:39 pm, Sumitava Mukherjee <sm...@cognobytes.com> wrote: >>> Hi all, >>> I need to randomly sample from a list where all choices have weights >>> attached to them. The probability of them being choosen is dependent >>> on the weights. >>> If say Sample list of choices are [A,B,C,D,E] and weights of the same >>> are [0.895,0.567,0.765,0.890,0.60] when I draw (say 2) samples then I >>> want the likeliness of them being chosen be in the order : D>A>C>E>B > > You mean A > D > C > E > B > >>> In short I mean if prob of a H is .9 and probability of T be 0.1 then >>> if I draw 10 samples, 9 should be H and 1 should be T. >>> >>> I coudn't find a function in the module random that does so. >>> Please can someone guide me how the above could be implemented [either >>> through some function which exists and I don't know or pointers to >>> some code snippets which does so]? >> >>>>>> [Oh, I forgot to mention. I am looking for sampling without replacement.] > > If you do sampling without replacement, you need to know the exact > number of each of A, B, C, D, E in the sample, not just their relative > frequency.
As far as I understand, you are given the exact number of each. It is one. The numbers given are not relative frequencies of appearance but weights to be attributed for picking them. -- Antoon Pardon -- http://mail.python.org/mailman/listinfo/python-list
