如何找到一组可被 7 整除的随机生成数字的最大值？

Question

I know this might be a very easy question but I can't get my head around it. The question asks to generate 357 random numbers between 8 and 254 (inclusive) and print out the largest generated number that is exactly divisible by 7.

I wrote this program:

import random

def main():
    for x in range(357):
      print (random.randint(8,254)*7),

print

main()

which generates the numbers but I don't know how to get the max number out of it. I would really appreciate any help

Answer 1

You could use a list comprehension to generate the random numbers and then apply a filter to only keep those that are divisible by 7:

import random

number = max(filter(lambda n: n % 7 == 0, [random.randint(8,254) for _ in range(357)]))

Answer 2

Concise one-liners are great, but here is an alternative approach that somewhat prioritizes readability for OP's reference. Namely, we save the randomly generated numbers in a list and perform sorting:

import random

def seven_max():
    nums = [random.randint(8,254) for _ in range(357)]
    nums.sort(reverse=True)
    for num in nums:
        if num % 7 == 0:
            return num
    return False # No such number

We first create a list of random numbers, defined as nums . Then, we sort the list in reverse order so that larger elements would come first. As we loop through this sorted array, we check if a number is divisible by 7. If it is, we return that number; if no number satisfies this condition, we return False .

Answer 3

You can use max with parameter key .

max((random.randint(8,254) for _ in range(357)),key =lambda x: x if x%7==0 else -1)

• (random.randint(8,254) for _ in range(357)) is generator for producing 357 random values between 8 to 254.

• key =lambda x: x if x%7==0 else -1 if number is divisible return it else -1. So, you get highest value that is divisible by 7.