How can I find the closest pair with the smallest difference in a single array?

I have a code that creates a list of 20 random integers between 1 and 1000. And In the case of multiple existences of closest pair, I have to display the smallest pair.

This is what I have so far:

import random

numbers = [random.randint(1, 100) for num in range(20)]
print(numbers)

>Solution :

I would suggesting using numpy:

import random
import numpy as np

numbers = np.array([random.randint(1, 100) for num in range(20)])
numbers.sort()
# calc diff:
diff = numbers[1:] - numbers[:-1]
# get index minimal diff:
argmin = diff.argmin()
pair = numbers[argmin:argmin+2]

Output:

print(numbers) # already sorted
>>> [ 1  6  7  8 11 15 18 37 47 54 60 61 61 73 73 78 82 85 87 94]
print(diff)
>>> [ 5  1  1  3  4  3 19 10  7  6  1  0 12  0  5  4  3  2  7]
print(pair) 
>>> array([61, 61])

This method will work in your case.