The sample method of the random module
The sample method of the random module returns a random sample of elements from a sequence. In the first parameter of the method, we specify the sequence, in the second parameter - the number of elements that we want to select randomly.
In the third optional named parameter k we can specify a list of elements to repeat. This allows us to increase the probability of selecting the given elements. Note that the third parameter of the method was added only starting with Python version 3.9.
Syntax
import random
random.sample(sequence, number of elements, [k=repeat repetition iteration reiterative])
Example
Let's get three random elements from the list:
lst = [1, 2, 3, 4, 5]
print(random.sample(lst, 3))
Result of code execution:
[2, 1, 5]
Example
Let's also try to take a sample of random elements from the tuple:
tpl = (1, 2, 3, 4, 5)
print(random.sample(tpl, 2))
Result of code execution:
[3, 2]
Example
You can also select elements from the sequence generated by the range function:
print(random.sample(range(0, 10), 3))
Result of code execution:
[0, 8, 9]
Example
Now let's take a list and use the counts parameter to assign repetitions to each element in the list. In our case, let the first element be repeated two times, the second three times, and the third four times. We also need to specify the parameter name k to output the number of elements:
lst = [1, 2, 3]
print(random.sample(lst, counts=[2, 3, 4], k=3))
This code is equivalent to the following:
lst = [1, 1, 2, 2, 2, 3, 3, 3, 3] # in fact such a list print(random.sample(lst, 3))
Example
Now let's try to take elements from the set:
st = {1, 2, 3, 4, 5}
print(random.sample(st, 2))
We will get the following error back:
[5, 2]
DeprecationWarning: Sampling from a set deprecated
since Python 3.9 and will be removed in a subsequent version.
print(random.sample(st, 2))
This is because since Python version 3.9 there is no way to take a sample from a set.
