CODEWITHSUNDEEP
pythonrandom
Lewis
Lewis

Reputation: 31

How to create a list of non duplicate numbers (Python)

So, I need a code for school where I need to generate 4 random numbers using randint and they can't be duplicates, I just cant seem to get my head around it. - Cheers

Upvotes: 2

Views: 162

Answers (2)

Mike - SMT
Mike - SMT

Reputation: 15236

We can accomplish a list of 4 random numbers by using a while loop to create a random number then append that number to a list only if that number does not already exist in the list. If we can append list then x -= 1 until x == 0 then the while loop will stop and the code will print out the list.

It will be different every time.

import random

x = 4
list_of_random_numbers = []
while x != 0:
    new_random_number = random.randint(0,999) # you can define any range of numbers here.
    if new_random_number not in list_of_random_numbers:
        list_of_random_numbers.append(new_random_number)
        x -= 1

print (list_of_random_numbers)

Edit:

Also as PM 2Ring said you can just check the length of the list as well:

import random

list_of_random_numbers = []
while len(list_of_random_numbers) < 4:
    new_random_number = random.randint(0,999) # you can define any range of numbers here.
    if new_random_number not in list_of_random_numbers:
        list_of_random_numbers.append(new_random_number)

print (list_of_random_numbers)

Upvotes: 3

cs95
cs95

Reputation: 403218

Use random.sample to randomly select 4 elements from a list.

import random
low, high = 0, 1000
w, x, y, z = random.sample(range(low, high) , 4)

Set low and high to your desired range from where you want to sample numbers.

Here's a less wasteful solution using randint (sorry for not seeing this earlier), if you want to generate any number in a wide range.

numbers = set()
while len(numbers) < 4:
    num = random.randint(low, high)
    if num not in numbers:
        numbers.add(num)

w, x, y, z = numbers

Upvotes: 3

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