Question

对于我的作业，我必须创建一个程序，让用户输入多个数字。我还想创建一个包含所有数字及其平均值的列表。

但是如何为数字列表创建代码？

我应该以0或-999之类的数字退出。

一行语法无效。

print (number_list[i], end = " ")

这是我的代码。

number_list = []
sum = 0.0

user_number = eval(input("Please enter a number (-999 quits): "))

# Loop until the user is ready to quit
while (user_number != -999):
    number_list.append(user_number)
    sum = sum + user_number
    user_number = eval(input("Please enter a number (-999 quits): "))

# Make sure the user entered something
if (len(number_list) != 0):
    # Compute average
    average = sum / len(number_list)

    # Do output
    print ("Using the numbers:")

    for i in range(len(number_list)):
        # Note the end = " " at the end will keep the output on
        #   the same line
        print (number_list[i], end = " ")

    # Note the \n at the start of this line is needed because
    #   the previous print statement ended with a comma.  This
    #   \n will move the cursor to the next line
    print ("\nThe average is:", average)
else:
    print ("No values were entered")

Answer 1

由于Python的缩进规则，任何复合语句都必须在其后至少缩进一条语句。

让我们关注代码的这一部分：

for i in range(len(number_list)):
print (number_list[i], end = " ")
print ("\nThe average is:", average)
else:
print ("No values were entered")

for循环是一个复合语句，因为它需要缩进的内容。您需要相应地缩进。像这样：

for i in range(len(eggs)):
    print(eggs[i])

遍历内容的pythonic方法是使用值而不是获取索引然后找到它。 Python的for循环比实际的foreach循环更像for循环。重新制作看起来像：

for spam in eggs:
    print(spam)

此外，您还要检查是否没有数字。为此，请使用普通的if语句，而不是循环中的一个。当主体部分（else或while）完成而没有for时，循环后面的break将运行。

此：

for spam in eggs:
    print(spam)
else:
    print("Nothing")

与此不同：

if eggs:
    for spam in eggs:
        print(spam)
else:
    print("Nothing")

这是固定部分：D

# If statement to check if list is truthy (nonempty)
if number_list:
    # Note the for loop's target 'number'
    for number in number_list:
        # Note indentation.
        print(number, end=" ")
    print("\nThe average is:", average)

else:
    print("No values were entered")

编辑：在本节上方的while循环之后，您也有缩进错误。我会留给您修复：）

如何打印数字及其平均值的列表？

1 个答案: