random模块

python random

doc 部分

 >>>import random    >>>help(random)

• randint(self, a, b)
  Return random integer in range [a, b], including both end points.
  返回a，b间随机的整数，包括b

  >>> random.randint(2,9)    8

• randrange(self, start, stop=None, step=1, ) Choose a random item from range(start, stop[, step]).This fixes the problem with randint() which includes the endpoint; in Python this is usually not what you want.
  返回start和end间随机数，不包括end

 >>> random.randrange(2,9)    6

• sample(self, population, k)
  Chooses k unique random elements from a population sequence.

  Returns a new list containing elements from the population while
  leaving the original population unchanged. The resulting list is
  in selection order so that all sub-slices will also be valid random
  samples. This allows raffle winners (the sample) to be partitioned
  into grand prize and second place winners (the subslices).

  Members of the population need not be hashable or unique. If the
  population contains repeats, then each occurrence is a possible
  selection in the sample.

  To choose a sample in a range of integers, use xrange as an argument

  This is especially fast and space efficient for sampling from a
  large population: sample(xrange(10000000), 60)
  随机返回populitation(list类型）中的包含k个元素的list。

 >>> random.sample(l,3)    [7, 3, 6]

• uniform(self, a, b)
  Get a random number in the range [a, b) or [a, b] depending on round
  返回a，b间数值，数值类型为浮点型。

 >>> random.uniform(2,9)    5.81482960618189

• random（）
  random(self)
  Get the next random number in the range [0.0, 1.0).
  返回0.0-1.0间的数字

 >>> random.random()    0.56701709066595