Python新手求助：实现无需修改代码的任意数量数字求和函数

Hey there! I see you're getting started with Python functions and want to expand your sum function to handle any number of inputs—great question! Let's break this down step by step.

问题分析 #

Your current sum function only accepts two parameters, which is why you have to modify it every time you want to add more numbers. Python has a handy feature called variable-length arguments (using *args) that lets you pass any number of positional arguments to a function.

改进后的求和函数 #

First, let's create a function that can take any number of numbers and sum them up. Also, we'll rename it to sum_numbers to avoid overwriting Python's built-in sum() function (that could cause unexpected issues later!):

def sum_numbers(*args):
    total = 0
    for num in args:
        total += num
    return total

# 测试一下
print(sum_numbers(5, 7))  # 输出12
print(sum_numbers(1, 2, 3, 4))  # 输出10
print(sum_numbers(10.5, 20.3, 5.2))  # 输出36.0

Or if you want to keep it super concise, you can use Python's built-in sum() directly inside your function:

def sum_numbers(*args):
    return sum(args)

结合用户输入的完整示例 #

Since you started writing a loop to ask for user input, let's put it all together into a working program that lets users enter as many numbers as they want, then calculates the total:

def sum_numbers(*args):
    return sum(args)

numbers_to_add = []
print("Enter numbers to sum, type 'done' when you're finished!")

while True:
    user_input = input("Enter a number: ")
    if user_input.lower() == 'done':
        break
    # 处理用户输入的非数字情况
    try:
        number = float(user_input)
        numbers_to_add.append(number)
    except ValueError:
        print("That's not a valid number—please try again.")

# 计算并输出结果
if numbers_to_add:
    total_sum = sum_numbers(*numbers_to_add)
    print(f"The total sum of your numbers is: {total_sum}")
else:
    print("You didn't enter any numbers to sum!")

关键点说明 #

• *args acts like a tuple that collects all the positional arguments passed to the function—you can loop through it just like any other iterable.
• Using try-except ensures your program doesn't crash if the user enters something that isn't a number.
• We use *numbers_to_add when calling the function to "unpack" the list of numbers into individual arguments for sum_numbers.

内容的提问来源于stack exchange，提问作者Viqtoh