CODEWITHSUNDEEP
pythonpython-3.x
Kaylee Upham
Kaylee Upham

Reputation: 1

I have a problem with an if-else statement

Whenever I run the following code, it always runs the else statement, not the if. It works perfectly when I don't have the or operator, but I need to use it. I don't know what to do!

print('What is your favourite Pokemon?')
FavPokemon = input()
if FavPokemon == ('Pikachu' or 'pikachu'):
    print('Me too!')
else:
    print('Cool! ' + FavPokemon + ' is a good Pokemon. My favourite is Pikachu though!')

Upvotes: 0

Views: 125

Answers (5)

Diptaraj
Diptaraj

Reputation: 1

EXPLANATION OF YOUR MISTAKE

You have done a little syntax mistake in writing the if statement. You have written

if FavPokemon == ('Pikachu' or 'pikachu'):

Here u have kept 'Pikachu' or 'pikachu' within parenthesis and checked FavPokemon outside that parenthesis with that == assignment operator sign.Doing these causes an error as it is unable to check with the condition.

CORRECT CODE

Correct code will be if you put the whole FavPokemon == 'Pikachu' or FavPokemon =='pikachu'into a parenthesis.This way it checks that whether FavPokemon is "Pikachu" or FavPokemon is "pikachu" and gives you the correct result.

The correct code will be:

print('What is your favourite Pokemon?')
FavPokemon = input()
if (FavPokemon == 'Pikachu' or FavPokemon =='pikachu'):
print('Me too!')
else:
print('Cool! ' + FavPokemon + ' is a good Pokemon. My favourite is Pikachu though!')

Upvotes: -3

bruno desthuilliers
bruno desthuilliers

Reputation: 77932

Programming languages are not natural languages and have different (and much stricter) grammars.

In natural languages, we all understand that "if a is equal to b or c" actually means "if a is equal to a or a is equal to b", but in programming language the formaly similar statement "if a == b or c" is parsed "if (expression) == (other expression)". Then each expression is evaluated (replaced with it's current final value) and only then the equality test is done. So 

if a == b or c:

is really:

d = b or c
if a == d:

Now the expression b or c returns the first of b or c which has a true value. Since in Python a non-empty string as a true value, your code:

if FavPokemon == ('Pikachu' or 'pikachu'):

is really:

name = ('Pikachu' or 'pikachu')
if FavPokemon == name:

and since 'Pikachu' is a non empty strings, this ends up as:

name = 'Pikachu'
if FavPokemon == name:

or more simply:

if FavPokemon == 'Pikachu':

The general rule is that if you want to test against multiple conditions, you have to write it explicitely, ie:

if a == b or a == c:

or

if a == b and x != y:

etc

Now if you want to test whether one object (string or whatever) is part of a collection of objects (tuple, list, etc), you can use the in operator:

a = 5
if a in (4, 5, 6):
    # ...

But in your case, since what you want is to test against the capitalized or uncapitalized version of the same word, you could instead transform the user's input (FavPokemon) in a "normalized" version and test against the "normalized" version of your string, ie instead of:

if FavPokemon in ('Pikachu', 'pikachu'):

you could write:

 FavPokemon = FavPokemon.lower()
 if FavPokemon == 'pikachu':

Note that this will be a bit less strict than the in version as it will accept "pIkachU" or "PIKACHU" or just any combination of upper/lowercase - but for your use case that's usually what's expected.

Upvotes: 1

Riddam Jain
Riddam Jain

Reputation: 117

Working Code:

print('What is your favourite Pokemon?')
FavPokemon = input()
if (FavPokemon == 'Pikachu' or FavPokemon == 'pikachu'):
    print('Me too!')
else:
    print('Cool! ' + FavPokemon + ' is a good Pokemon. My favourite is Pikachu though!')

Useful Links python-or-operator/

Upvotes: 0

Mark Ransom
Mark Ransom

Reputation: 308520

The statement isn't working because or doesn't do what you think it does. The expression ('Pikachu' or 'pikachu') evaluates to a single string, 'Pikachu'. The == then compares against that only.

What you probably want is:

if FavPokemon in ('Pikachu', 'pikachu'):

Upvotes: 4

artemis
artemis

Reputation: 7281

print('What is your favourite Pokemon?')
 FavPokemon = input()
 if FavPokemon == 'Pikachu' or FavPokemon == 'pikachu':
     print('Me too!')
 else:
     print('Cool! ' + FavPokemon + ' is a good Pokemon. My favourite is Pikachu though!')

Is what your code needs to be. Your if statement needs to be changed. The expression before, If x == (a or b) will always evaluate to true. You were not checking if the FavPokemon variable was actually Pikachu or pikachu, you were checking is the condition (a or b) is true, which in that syntax, it is always true.

See https://www.w3schools.com/python/python_conditions.asp

Upvotes: 2

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