Big array with random numbers with python

Question

I need to generate a big array (or list) with random numbers ( 10⁵ numbers) . I was trying like that:

vet = random.sample(range(10),100000)

But when I try to run :

vet = random.sample(range(10),10000)

File "/usr/lib/python2.7/random.py", line 320, in sample raise ValueError("sample larger than population") ValueError: sample larger than population

Any solution?

tkns

Considering the size of that list, you might want to consider an array library like [numpy](http://numpy.scipy.org/): `import numpy; vet = numpy.random.randint(0, 10, 10000)` — Snowball, Aug 28 '12 at 21:58

score 31 · Accepted Answer · edited Nov 26 '21 at 20:33

31

What you want is

[random.random() for _ in xrange(100000)]

From the random module documentation:

random.sample(population, k) Return a k length list of unique elements chosen from the population sequence. Used for random sampling without replacement.

so when calling random.sample(range(10), 100000) you're trying to extract 100000 unique elements in a sequence of length 10 which obviously can't work.

Note that

random.random() returns a floating value between [0 ; 1)
random.randrange([start], stop[, step]) returns a random element from the sequence range([start], stop[, step])
random.randint(a, b) returns an integer value in [a ; b]
when using random.sample, the equality len(population) >= k must hold

edited Nov 26 '21 at 20:33

ThisClark

14,352
10
69
100

answered Aug 28 '12 at 21:41

marchelbling

1,909
15
23

Can't find module xrange – ThisClark Apr 05 '21 at 20:21
1

If you're using Python3, `xrange` (which was just a "lazy" `range`) is now simply `range`. See e.g. https://stackoverflow.com/questions/15014310/why-is-there-no-xrange-function-in-python3. – marchelbling Nov 26 '21 at 14:18

score 13 · Answer 2 · answered Aug 28 '12 at 21:39

13

I think you're after something like this:

vet = [random.randint(1,10) for _ in range(100000)]

answered Aug 28 '12 at 21:39

g.d.d.c

46,865
9
101
111

score 2 · Answer 3 · answered Apr 24 '18 at 15:49

You can you the numpy function and create an array with N space filled with a random number

import numpy as np

vector_size = 10000

one_dimensional_array  = np.random.rand(vector_size)
two_dimensional_array  = np.random.rand(vector_size, 2)
tree_dimensional_array = np.random.rand(vector_size, 3)
#and so on

numpy.random.rand

You can create matrix of random numbers using the function below and arrays also.

Big array with random numbers with python

3 Answers3

Linked