My 'if statement' won't work

Question

def main():
    while True:
        operation = raw_input('Choose an operation: ')

        if operation == 1:
            number_1 = int(raw_input("What is the first number you want to subtract? "))
            number_2 = int(raw_input("What do you want to subtract from it? "))
            sum = number_1 - number_2
            print('The answer is...')
            print(sum)
            break

        if operation == 2:
            number_1 = int(raw_input("What is the first number you want to subtract? "))
            number_2 = int(raw_input("What do you want to subtract from it? "))
            sum = number_1 - number_2
            print('The answer is...')
            print(sum)
            break

        if operation == 3:
            number_1 = int(raw_input("What is the first number you want to subtract? "))
            number_2 = int(raw_input("What do you want to subtract from it? "))
            sum = number_1 - number_2
            print('The answer is...')
            print(sum)
            break

        if operation == 4:
            number_1 = int(raw_input("What is the first number you want to subtract? "))
            number_2 = int(raw_input("What do you want to subtract from it? "))
            sum = number_1 - number_2
            print('The answer is...')
            print(sum)
            break

        else:
            print('Invalid operation')
            break
main()

When I try to input a number it doesn't recognise it and prints Invalid operation

That is not true; in Python 2.x `input()` is equivalent to `eval(raw_input())`. — pp_, Feb 10 '16 at 23:16

score 2 · Answer 1 · answered Feb 10 '16 at 23:10

2

You have to convert the input to an integer with int():

operation = int(raw_input('Choose an operation: '))

answered Feb 10 '16 at 23:10

pp_

3,435
4
19
27

score 0 · Answer 2 · answered Feb 10 '16 at 23:11

0

set your if statements to something like:

if int(operation) == 1

or

if operation == str(1)

answered Feb 10 '16 at 23:11

Simon

9,762
15
62
119

score 0 · Answer 3 · answered Feb 10 '16 at 23:11

0

You have to compare strings:

if operation == "1":

answered Feb 10 '16 at 23:11

gollum

2,472
1
18
21

score 0 · Answer 4 · answered Feb 10 '16 at 23:17

operation needs to be an int if you have it checking against a int for your if statements.

operation = raw_input('Choose an operation: ')

should be

operation = int(raw_input('Choose an operation: '))

As a side note, make sure you proofread your code before asking. :)

My 'if statement' won't work

4 Answers4