计算while循环中raw_input数据的平均值

Question

同事python开发人员。我有一项任务，我似乎无法破解，我的导师是MIA。我需要编写一个只使用while循环，if，elif和else语句的程序：

• 不断要求用户使用int(raw_input())输入任意随机正整数
• 一旦用户输入-1，程序就需要结束
• 然后，程序必须计算用户输入的数字的平均值（不包括-1）并将其打印出来。

这就是我到目前为止：

num = -1
counter = 1
anyNumber = int(raw_input("Enter any number: "))
while anyNumber > num:
        anyNumber = int(raw_input("Enter another number: "))
        counter += anyNumber
        answer = counter + anyNumber        
print answer
print "Good bye!"

Answer 1

您需要在代码末尾添加计算平均值。

为此，计算while循环运行的次数，并将该值除以该值。

此外，您的代码每次都会在答案中添加一个因为行 - answer = counter + anyNumber，这不会产生正确的平均值。并且您缺少存储第一个输入数字，因为代码连续输入两个输入。这是一个固定版本：

num = -1
counter = 0
answer = 0
anyNumber = int(raw_input("Enter any number: "))
while anyNumber > num:
    counter += 1
    answer += anyNumber
    anyNumber = int(raw_input("Enter another number: "))
if (counter==0): print answer #in case the first number entered was -1
else:
    print answer/counter #print average
print "Good bye!"

Answer 2

尝试以下内容并询问您可能遇到的任何问题

counter = 0
total = 0
number = int(raw_input("Enter any number: "))
while number != -1:
    counter += 1
    total += number
    number = int(raw_input("Enter another number: "))
if counter == 0:
    counter = 1  # Prevent division by zero
print total / counter

Answer 3

我认为还有另一个问题：

anyNumber = int(raw_input("Enter any number: "))
while anyNumber > num:
        anyNumber = int(raw_input("Enter another number: "))

变量anyNumber的值在循环之前和循环开始时更新，这意味着您将要输入的第一个值永远不会被考虑在平均值中。

Answer 4

一个不同的解决方案，使用更多功能，但更安全。

import numpy as np

numbers = []

while True:
    # try and except to avoid errors when the input is not an integer.
    # Replace int by float if you want to take into account float numbers
    try:
        user_input = int(input("Enter any number: "))

        # Condition to get out of the while loop
        if user_input == -1:
            break

        numbers.append(user_input)
        print (np.mean(numbers))

    except:
        print ("Enter a number.")

Answer 5

你不需要保存总数，因为如果数字真的很大，你可以有溢出。仅使用avg应该足够了：

STOP_NUMBER = -1
new_number = int(raw_input("Enter any number: "))
count = 1
avg = 0
while new_number != STOP_NUMBER:
    avg *= (count-1)/count
    avg += new_number/count
    new_number = int(raw_input("Enter any number: "))
    count += 1

Answer 6

我建议跟随。

counter = input_sum = input_value = 0

while input_value != -1:
    counter += 1
    input_sum += input_value
    input_value = int(raw_input("Enter any number: "))

try:
    print(input_sum/counter)
except ZeroDivisionError:
    print(0)

您可以避免使用两个raw_input并使用while循环内的所有内容。

Answer 7

还有另一种做法..

nums = []
while True:
    num = int(raw_input("Enter a positive number or to quit enter -1: "))
    if num == -1:
        if len(nums) > 0:
            print "Avg of {} is {}".format(nums,sum(nums)/len(nums))  
        break
    elif num < -1:
        continue
    else:
        nums.append(num)

Answer 8

虽然@ nj2237提供的解决方案也很完美，但这是我自己想要做的事情。

# Initialization
sum = 0
counter = 0
stop = False

# Process loop
while (not stop):
    inputValue = int(raw_input("Enter a number: "))

    if (inputValue == -1):
        stop = True
    else:
        sum += inputValue
        counter += 1 # counter++ doesn't work in python

# Output calculation and display
if (counter != 0):
    mean = sum / counter
    print("Mean value is " + str(mean))

print("kthxbye")