CODEWITHSUNDEEP
pythonpython-3.x
goatpasta
goatpasta

Reputation: 3

How come a number inputted by a user isn't recognized if I try to find it's index?

Code:

a = [1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89]

num = input('Enter a number: ')
a.append(int(num))
a.sort()
print(a)
print(a.index(num))

Output:

Enter a number: 78
[1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 78, 89]
Traceback (most recent call last):
  File "C:\Users\linda keator\PycharmProjects\game_1\main.py", line 8, in <module>
    print(a.index(num))
ValueError: '78' is not in list

I made a python program that requests input from the user, which adds to the list of numbers above (fibonacci sequence for no reason).

How do I program it so that it will return the index of the number added from the input? It's sorted smallest to biggest with .sort(). It says that 78 isn't in the list, even though it's being displayed as part of list just above the error message. What's the issue in my code?

Upvotes: 0

Views: 46

Answers (3)

Daydream404
Daydream404

Reputation: 1

You are adding 'str' to a list. Try it like this:

a = [1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89]

num = input("Enter Number:")

#a.append(int(num)) here you are appending str

print(type(num)) 
#Output <class 'str'>

b = int(num)
a.append(b)
a.sort()
print(a)
print(a.index(b))

Upvotes: 0

astrochun
astrochun

Reputation: 1796

The last line of code you have it looking for a str, not an integer:

a = [1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89]

num = input('Enter a number: ')
a.append(int(num))
a.sort()
print(a)
print(a.index(int(num)))

Upvotes: 0

ddejohn
ddejohn

Reputation: 8962

You're attempting to find the index of num which is a str object because it was the return value of the input() function which always returns a str. You correctly cast num to int when you appended to a, but this isn't a permanent modification. Before anything you need to do

num = int(num)

Then you can add it to your list of numbers. A safer approach to this would be to get user input via a while loop:

def get_integer_input():
    while True:
        try:
            num = int(input("Enter a number: "))
            break
        except ValueError:
            print("Invalid input, try again!\n")
    return num

Upvotes: 2

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