Round off numbers in python

Question

我有一个数字[0,10,20,30,40,50]的列表，现在此列表将由诸如33，43的随机数附加，我每次在列表中未附加任何编号时都要检查该列表，并且我希望将它们四舍五入为30和40。

Answer 1

Use the round() built-in function. In conjuction with a list comprehension , can give us an expressive one-line function!

def round_list(l):
    return [int(round(i, -1)) for i in l]

Sample output:

l = [24, 34, 41, 40, 12, 434, 53, 53]
print round_list(l)
>>> [20, 30, 40, 40, 10, 430, 50, 50]

Answer 2

In order to round to the nearest 10 you can:

1. Divide the number by 10
2. Use round() on the new number
3. Multiply the rounded number by 10

The code below should contain what you need:

import random

l = [0.0, 10.0, 20.0, 30.0, 40.0, 50.0]

# generate a random number
random_number = random.uniform(30, 100)

# round the number to nearest 10
def round_number(num):
    x = round(num/10) * 10
    return x

rounded_number = round_number(random_number)

# append to the list
l.append(rounded_number)

Testing the above:

>>> print random_number
64.566245501
>>> print rounded_number
60.0
>>> print l
[0.0, 10.0, 20.0, 30.0, 40.0, 50.0, 60.0]