- YouTube
youtu.be
Auf YouTube findest du die angesagtesten Videos und Tracks. Außerdem kannst du eigene Inhalte hochladen und mit Freunden oder gleich der ganzen Welt teilen.

I’m currently doing Dr. Charles Severence’s lessons on FreeCodeCamp to try to learn Python3. I’m on lesson exercise 02_03 and confused about multiplying floating-point and integer values.

The goal is to write a Python program multiplying hours worked by pay rate to come up with a pay quantity.

This is the code I wrote:

h = input("Enter hours: ")
r = input("Enter pay rate: ")
p = float(h) * r

I got a traceback error, and the video said the correct way to solve said error was change Line 3 from p = float(h) * r to p = float(h) * float(r).

However, what I’m confused about is why would I need to change r to a floating-point value when it’s already a floating-point value (since it’d be a currency value like 5.00 or something once I typed it in per the input() command*?

What am I missing here?

 

*I can’t remember: are the individual commands in a python line called “commands”?

 

 

Edit: Wrote plus signs in my post here instead of asterisks. Fixed.

 

EDIT: Thanks to @Labna@lemmy.world and @woop_woop@lemmy.world. I thought that the input() function was a string until the end-user types something in upon being prompted, and then becomes a floating-point value or integer value (or stays a string) according to what was typed.

This is incorrect: the value is a string regardless of what is typed unless it is then converted to another type.

  • Labna@lemmy.world
    6·
    2 months ago

    I think I understand where you get confused. The returned value of the input function is always a string, you have to convert it into a number before using it in calculation. Otherwise the auto-parser will convert everything into string. Even if you use * or **.

    • EveryMuffinIsNowEncryptedOPEnglish
      1·
      2 months ago

      But I thought the “value” doesn’t exist until the end-user types in the value, due to the use of input(). So it starts off as a string, then becomes whatever is typed in, which then gets filtered through the next line. So if I type 3, it’ll be considered as an integer, and likewise as a float if I type 3.00.

      • woop_woop@lemmy.world
        4·
        2 months ago

        the signature for the input function (that’s what it’s called instead of command) is

        def input(__prompt: Any = ...) -> str

        which means it’s always going to return a string.

        So it starts off as a string, then becomes whatever is typed in

        there’s no real way for something to do that automatically without a much more robust setup.

        this snippet proves that

        test_int = input('enter integer:')
print(type(test_int))
test_float = input('enter float:')
print(type(test_float))
test_str = input('enter string:')
print(type(test_str))

>> <class 'str'>
>> <class 'str'>
>> <class 'str'>

        it is the responsibility of your program to validate and do whatever you want with the result, and part of that can include casting it to a different type.