given a set of integers and a value for which you need to find the nearest one.

def nearest_number(numbers, target):
    numbers.sort()
    diff = target - numbers[0]
    for i in range(1, len(numbers)):
        if target - numbers[i] < diff:
            diff = target - numbers[i]
    return numbers[0] + diff

nearest_number([1, 2, 3, 4, 5], 3)