如何打印数字及其平均值的列表？

Question

For my assignment, I have to create a program that lets the user enter several numbers. I also want to create a list with all the numbers and their average.

But how do I create a code for the list of numbers?

I should exit with a number such as 0 or -999.

One line has invalid syntax.

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

Here is my code.

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

Because of Python's indentation rules, any compound statement needs to have at least one statement indented after it.

Let's focus on this section of your code:

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

A for loop is a compound statement as it needs stuff indented after it. You need to indent them accordingly. Something like:

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

The pythonic way to loop over stuff is just to use the value instead of getting the index and then finding it. Python's for loop is more like a foreach loop than an actual for loop. A remake would look like:

for spam in eggs:
    print(spam)

Also, you have a check for if there aren't any numbers. Use a normal if statement for that, not one in the loop. The else behind a loop will run when the main part ( while or for ) finishes without a break .

This:

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

Is not the same as this:

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

Here's the fixed section :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")

EDIT: You also have indentation errors after the while loop above this section. I'll leave that to you to fix :)