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Python Python Basics (2015) Logic in Python Try and Except

Posted by Disha De
Disha De
686 Points

You're doing great! Just one more task but it's a bigger one. Right now, we turn everything into a float.

You're doing great! Just one more task but it's a bigger one.

Right now, we turn everything into a float. That's great so long as we're getting numbers or numbers as a string. We should handle cases where we get a non-number, though.

Add a try block before where you turn your arguments into floats.

Then add an except to catch the possible ValueError. Inside the except block, return None.

If you're following the structure from the videos, add an else: for your final return of the added floats

trial.py 
def add(n1, n2)
    try:
        a = float(n1)
        b = float(n2)
    except ValueError:
        return None
    else:
        return True

1 Answer

andren
andren
28,558 Points
andren
andren
28,558 Points

There are two issues:

  1. You are missing a colon : after your function declaration
  2. In the else block you are meant to return the result of adding the two numbers together, you are just returning the Boolean True.

If you add the colon and add the two numbers together like this:

def add(n1, n2): # <- Added :
    try:
        a = float(n1)
        b = float(n2)
    except ValueError:
        return None
    else:
        return a + b # Return two numbers added together

Then your code will pass.