What this error "not all arguments converted during string formatting" means?

Question

I am entering two numbers from the user to get the GCD. Error showing at return gcd(a,a%b)

Attach is the code

def gcd(a,b):
   if b==0:
      return a
   return gcd(a,a%b)


a = input("Enter first number: ")
b = input("Enter second number: ")
res = gcd(a,b)
print("GCD of {1} and {2} is {3}".format(a, b,res))

TypeError: not all arguments converted during string formatting

You aren't converting input string to number.... Try `a = int(input("Enter first number: "))` and for `b` too — Andrej Kesely, Aug 10 '19 at 19:10
Mention the python version please. For me, just removing the 1,2,3 from print statement worked. I am using Python 3.7. — Akash Kumar, Aug 10 '19 at 19:12
That didn't work. The error changed to "tuple index out of range" at line 10 — Ishpreet_Singh, Aug 10 '19 at 19:13
did you try after removing that. I faced the same error and was resolved after removing the numbers from print — Akash Kumar, Aug 10 '19 at 19:14
Duplicate: [How can I read inputs as numbers?](/q/20449427/4518341) — wjandrea, Jul 23 '22 at 20:44

score 0 · Answer 1 · edited Jul 23 '22 at 20:46

There are three problems:

The function input() returns a string. So you need to convert the result to a number or integer using int().
The algorithm is wrong. The recursive call should be return gcd(b, a%b).
The positional placeholders in format() are zero based. So the correct placeholders are {0}, {1} and {2}

The fixed code is:

def gcd(a,b):
   if b==0:
       return a
   return gcd(b, a%b)


a = int(input("Enter first number: "))
b = int(input("Enter second number: "))
res = gcd(a,b)
print("GCD of {0} and {1} is {2}".format(a, b, res))

What this error "not all arguments converted during string formatting" means?

1 Answers1