numpy.random.mtrand.RandomState.random_integers

RandomState.random_integers(low, high=None, size=None)

Return random integers between low and high, inclusive.

Return random integers from the “discrete uniform” distribution in the closed interval [low, high]. If high is None (the default), then results are from [1, low].

Parameters :

low : int

Lowest (signed) integer to be drawn from the distribution (unless high=None, in which case this parameter is the highest such integer).

high : int, optional

If provided, the largest (signed) integer to be drawn from the distribution (see above for behavior if high=None).

size : int or tuple of ints, optional

Output shape. Default is None, in which case a single int is returned.

Returns :

out : int or ndarray of ints

size-shaped array of random integers from the appropriate distribution, or a single such random int if size not provided.

See also

random.randint

Similar to random_integers, only for the half-open interval [low, high), and 0 is the lowest value if high is omitted.

Notes

To sample from N evenly spaced floating-point numbers between a and b, use:

a + (b - a) * (np.random.random_integers(N) - 1) / (N - 1.)

Examples

>>> np.random.random_integers(5)
4
>>> type(np.random.random_integers(5))
<type 'int'>
>>> np.random.random_integers(5, size=(3.,2.))
array([[5, 4],
       [3, 3],
       [4, 5]])

Choose five random numbers from the set of five evenly-spaced numbers between 0 and 2.5, inclusive (i.e., from the set ):

>>> 2.5 * (np.random.random_integers(5, size=(5,)) - 1) / 4.
array([ 0.625,  1.25 ,  0.625,  0.625,  2.5  ])

Roll two six sided dice 1000 times and sum the results:

>>> d1 = np.random.random_integers(1, 6, 1000)
>>> d2 = np.random.random_integers(1, 6, 1000)
>>> dsums = d1 + d2

Display results as a histogram:

>>> import matplotlib.pyplot as plt
>>> count, bins, ignored = plt.hist(dsums, 11, normed=True)
>>> plt.show()

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