numpy.random.uniform#
- random.uniform(low=0.0, high=1.0, size=None)#
Draw samples from a uniform distribution.
Samples are uniformly distributed over the half-open interval
[low, high)
(includes low, but excludes high). In other words, any value within the given interval is equally likely to be drawn byuniform
.Note
New code should use the
uniform
method of aGenerator
instance instead; please see the Quick Start.- Parameters:
- lowfloat or array_like of floats, optional
Lower boundary of the output interval. All values generated will be greater than or equal to low. The default value is 0.
- highfloat or array_like of floats
Upper boundary of the output interval. All values generated will be less than or equal to high. The high limit may be included in the returned array of floats due to floating-point rounding in the equation
low + (high-low) * random_sample()
. The default value is 1.0.- sizeint or tuple of ints, optional
Output shape. If the given shape is, e.g.,
(m, n, k)
, thenm * n * k
samples are drawn. If size isNone
(default), a single value is returned iflow
andhigh
are both scalars. Otherwise,np.broadcast(low, high).size
samples are drawn.
- Returns:
- outndarray or scalar
Drawn samples from the parameterized uniform distribution.
See also
randint
Discrete uniform distribution, yielding integers.
random_integers
Discrete uniform distribution over the closed interval
[low, high]
.random_sample
Floats uniformly distributed over
[0, 1)
.random
Alias for
random_sample
.rand
Convenience function that accepts dimensions as input, e.g.,
rand(2,2)
would generate a 2-by-2 array of floats, uniformly distributed over[0, 1)
.random.Generator.uniform
which should be used for new code.
Notes
The probability density function of the uniform distribution is
\[p(x) = \frac{1}{b - a}\]anywhere within the interval
[a, b)
, and zero elsewhere.When
high
==low
, values oflow
will be returned. Ifhigh
<low
, the results are officially undefined and may eventually raise an error, i.e. do not rely on this function to behave when passed arguments satisfying that inequality condition. Thehigh
limit may be included in the returned array of floats due to floating-point rounding in the equationlow + (high-low) * random_sample()
. For example:>>> x = np.float32(5*0.99999999) >>> x 5.0
Examples
Draw samples from the distribution:
>>> s = np.random.uniform(-1,0,1000)
All values are within the given interval:
>>> np.all(s >= -1) True >>> np.all(s < 0) True
Display the histogram of the samples, along with the probability density function:
>>> import matplotlib.pyplot as plt >>> count, bins, ignored = plt.hist(s, 15, density=True) >>> plt.plot(bins, np.ones_like(bins), linewidth=2, color='r') >>> plt.show()