numpy.random.
randn
Return a sample (or samples) from the “standard normal” distribution.
Note
This is a convenience function for users porting code from Matlab, and wraps standard_normal. That function takes a tuple to specify the size of the output, which is consistent with other NumPy functions like numpy.zeros and numpy.ones.
standard_normal
numpy.zeros
numpy.ones
New code should use the standard_normal method of a default_rng() instance instead; see random-quick-start.
default_rng()
If positive int_like arguments are provided, randn generates an array of shape (d0, d1, ..., dn), filled with random floats sampled from a univariate “normal” (Gaussian) distribution of mean 0 and variance 1. A single float randomly sampled from the distribution is returned if no argument is provided.
(d0, d1, ..., dn)
The dimensions of the returned array, must be non-negative. If no argument is given a single Python float is returned.
A (d0, d1, ..., dn)-shaped array of floating-point samples from the standard normal distribution, or a single such float if no parameters were supplied.
See also
Similar, but takes a tuple as its argument.
normal
Also accepts mu and sigma arguments.
Generator.standard_normal
which should be used for new code.
Notes
For random samples from
System Message: WARNING/2 (N(\mu, \sigma^2))
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sigma * np.random.randn(...) + mu
Examples
>>> np.random.randn() 2.1923875335537315 # random
Two-by-four array of samples from N(3, 6.25):
>>> 3 + 2.5 * np.random.randn(2, 4) array([[-4.49401501, 4.00950034, -1.81814867, 7.29718677], # random [ 0.39924804, 4.68456316, 4.99394529, 4.84057254]]) # random