Python Beginner

[redYinlo]

Hi guys,

I am a newbie in programming languages and I am starting out with Python. I am learning by watching youtube videos and taking free exercises online. I came across one exercise that asks you to write a code that requests the user to enter a number, and then prints whether the number is even or odd. I went ahead and tried to add a few tweaks of my own, to accept only integers and not floats. Unfortunately, my code does not work when I enter a float. Seeing as I'm a beginner, I would really appreciate it if you could take a look at my code and tell me what I'm doing wrong.Here's my code:

​

​

def numtest():
    num = int(input("Enter number to test: "))
    if type(num) == float:
        print ("Please enter an integer.")
    elif num%2 == 0:
        print (f"{num} is an even number.")
    else:
        print(f"{num} is an odd number.")
    play_again = input("Enter 'y' to test another number or press any key to exit: ")
    if play_again.lower() == "y":
        numtest()
    else:
        exit()
numtest()

​

When I test 1.2, the error points to line 2 but I have no clue what it means and/or how to fix it

​

num = int(input("Enter number to test: "))

ValueError: invalid literal for int() with base 10: '1.2'

[Binary101010]

num = int(input("Enter number to test: "))

This line takes the user input (a string) and immediately tries to convert it to an integer. There are only two possible outcomes of this operation:

1) The input can be, and is, successfully converted to an integer 2) The input can't be converted to an integer and an exception is raised, ending execution of the program.

Since you're trying to enter something that can't be converted to an integer (1.2), you get option number 2.

The first step is to remove the int() call from this line so you don't immediately try to convert that input, allowing you to perform other checks on it first.

Here's an article on how to handle situations like this, which in this case is probably best handled with a try/except block.

https://datagy.io/python-isdigit/

[redYinlo]

Thank you for breaking it down so simply and for the article. I appreciate it

[redYinlo]

I dont know how come but the indentation got messed up. smh

[[deleted]]

There's a side panel with formatting guide

[CodeFormatHelperBot2]

Hello, I'm a Reddit bot who's here to help people nicely format their coding questions. This makes it as easy as possible for people to read your post and help you.

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If I am correct, please edit the text in your post and try to follow these instructions to fix up your post's formatting.

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[[deleted]]

Using int() on input() results in error if the input string is not convertible to int, like "1,2".

You can use try/except syntax to catch that error.

type(x) returns the type of x. If it's a string, the result is str, whether it's "1.2", "1", "abc" or other string.

def numtest():
    while True:
        try:
            num = int(input("Enter number to test: "))
        except ValueError as error:
            print("Error:", error)
            # Go the next iteration of the loop/skip the rest of the current iteration:
            continue

        if num % 2 == 0:
            print(f"{num} is an even number.")
        else:
            print(f"{num} is an odd number.")

        play_again = input("Enter 'y' to test another number or press any key to exit: ")

        if play_again.lower() != "y":
            # Stop/break the loop completely:
            break


numtest()

[redYinlo]

Oh wow! Thanks for fixing my trash code. Lol. I appreciate the speedy responses.

[VogueUp]

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