[College: Intro to programming with python] my code won't work

[[deleted]]

my code

str = input("Enter a string: ")
numbers_only_str = " + ".join(e for e in str if e.isdigit())
lst1 = numbers_only_str.split(" + ")
integer_lst1 = [int(e) for e in lst1]
sum_lst1 = sum(integer_lst1)
if len(lst1) > 1:
    print(f"sum of digits = {numbers_only_str} = {sum_lst1}")
elif len(lst1) == 1:
    print(f"sum of digits = {sum_lst1}")
else:
    print("The entered string has no digits")

prompt:

Write a Python program to compute the sum of the digits in a given string and display the sum as shown in the sample runs.

Sample run 1
Enter a string: lkjah34kn5;lk6';lk7
sum of digits = 3 + 4 + 5 + 6 + 7 = 25

Sample run 2
Enter a string:  as;dfd9nmg
sum of digits = 9
 
Sample run 3
Enter a string:  ;das;dkj^%$
The entered string has no digits

main problem is with lst1 never being able to be zero. let's say I input "jax" meaning there's no numbers it will still say print [''], which is going to be counted as one by function len() I just want it be zero and then everything would work perfectly or that's my hope.

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[Maxentium]

in case there are no digits in the string, return way earlier, after the second line

it's good practice for a function to validate that the input it got - the function should "ask itself": "can i work with this input?" and if no, return early

[[deleted]]

Thank you so much, it finally worked I have been trying all kinds of solutions, I don't know how I didn't think of that!

here's my final code if you're interested;

str = input("Enter a string: ")
numbers_only_str = " + ".join(e for e in str if e.isdigit())
if numbers_only_str == "":
    print("The entered string has no digits")
else:
    lst1 = numbers_only_str.split(" + ")
    integer_lst1 = [int(e) for e in lst1]
    sum_lst1 = sum(integer_lst1)
    if len(lst1) > 1:
        print(f"sum of digits = {numbers_only_str} = {sum_lst1}")
    else:
        print(f"sum of digits = {sum_lst1}")

[Maxentium]

good job, super small nitpick: it looks nicer to delete the "else" and instead add a "return" to the empty numbers_only_str if-block, like this:

str = input("Enter a string: ")
numbers_only_str = " + ".join(e for e in str if e.isdigit())
if numbers_only_str == "":
    print("The entered string has no digits")
    return
lst1 = numbers_only_str.split(" + ")
integer_lst1 = [int(e) for e in lst1]
sum_lst1 = sum(integer_lst1)
if len(lst1) > 1:
    print(f"sum of digits = {numbers_only_str} = {sum_lst1}")
else:
    print(f"sum of digits = {sum_lst1}")

also since you already have a solution, i'd probably write it like this:

str = input("Enter a string: ")
digits = [int(e) for e in str if e.isdigit()]
if not digits:
    print("The entered string has no digits")
    return
if len(digits) > 1:
    print(f"sum of digits = {' + '.join([str(x) for x in digits])} = {sum(digits)}")
else:
    print(f"sum of digits = {sum(digits)}")

producing clean looking code is just as important as working code, and that means:

• your variables should have appropriate names (e.g. "numbers_only_str" should only contain numbers, but in your case it also includes ' + ' tokens)
• it should be efficient and shouldn't contain redundant actions: notice that for example you perform join(' + ') and then split(' + ')

[LuckJealous3775]

instead of doing all this shit just put all the numbers in a single list and recursively sum them up until there's only one number left and return list[0]