如何将一个变量的输入变成一个列表？

Question

So I am new to python and started to design and simple calculator. What it does right now is just ask for number, then ask for operation, then ask for number... etc. I want the numbers that are inputted from the user to be stored in a list. Right now when I print(input_num) it just prints the last inputted number. I want to be able to print all of the numbers inputted by the user. Thanks, I hope this was more specific than the last time I posted this.

try:
    done = False
    next1 = False
    input_num = []
    print("*** Enter done to calculate result ***")
    print("*** Operation list: +, -, *, / ***")
    while not done:
        input_num = float(input("Enter a number: "))
        next1 = True
        while next1:
            input_operation = input("Enter an operation, or  enter \"done\" to finish: ")
            next1 = False
            if input_operation == "done":
                done = True
    print(input_num)
except ValueError:
    print("*** Invalid Input! ***")

Answer 1

You're looking for .append() . This will add the input to the end of your list, so in your case it would be.

input_num.append(float(input("Enter a number: ")))

rather than

input_num = float(input("Enter a number: "))

In the current state it's just setting input_num to the value of the input over and over.

You can read more on lists here (python 3.8.5 docs).

Answer 2

While @Codesidian has already provided you a response, I wanted to also address the boolean variables defined. You don't need to define so many boolean variables. Instead you can use True and False in your while loops. Also, you need only one while loop for the entire processing.

I have simplified your code. Hope this helps. The functionality has not changed.

try:
    input_num = []
    print("*** Enter done to calculate result ***")
    print("*** Operation list: +, -, *, / ***")
    while True:
        input_num.append(float(input("Enter a number: ")))
        input_operation = input("Enter an operation, or  enter \"done\" to finish: ")
        if input_operation.lower() == 'done':
            break
        else:
            input_num.append(input_operation)
    print(input_num)
except ValueError:
    print("*** Invalid Input! ***")

Output:

For a good run:

*** Enter done to calculate result ***
*** Operation list: +, -, *, / ***
Enter a number: 12.25
Enter an operation, or  enter "done" to finish: +
Enter a number: 15.75
Enter an operation, or  enter "done" to finish: done
[12.25, '+', 15.75]

When a bad value is entered:

*** Enter done to calculate result ***
*** Operation list: +, -, *, / ***
Enter a number: 45
Enter an operation, or  enter "done" to finish: +
Enter a number: 35
Enter an operation, or  enter "done" to finish: -
Enter a number: a
*** Invalid Input! ***