CODEWITHSUNDEEP
python
Robin311
Robin311

Reputation: 253

Think Python (How to think like a computer scientist) - Excercise 8.4 Duckling question

I have an additional question related to the link below:

Think Python (How to think like a computer scientist) - Excercise 8.4

I tried using this method to produce a solution to the ducklings problem, but it's not producing the answer I wanted. I wish to know what is wrong with my code because I can't seem to figure it out :(

enter image description here

as you can see, I think I set the conditions right : when the letter is O or Q, you add 'u' between the prefix and suffix, and you print everything else the way it was. But the thing is, the output is adding 'u' to everything, not just O or Q.

Is there some kind of syntax error I did wrong? I'm having a hard time trying to understand what I did wrong and I would appreciate it if anyone could point out my mistake and how to fix it. Thanks.

Upvotes: 0

Views: 170

Answers (2)

sahasrara62
sahasrara62

Reputation: 11238

here, if letter =='O' or 'Q' is read as if (letter=='O') or 'Q' .

ie it check, that value of letter is O or not. and using or operations. so when Letter=='O' is True and Q is always True.

so in OR operation True&True=True, True&False=True , False&True=True and False&False=False.

so since Q will be always True, hence the condition if letter=='O' or 'Q' will be always true and next statement print(letter+'u'+suffix) always executed.

to avoid this, you just also need to check if letter=='Q' or not.This will help you to get True or False when Letter is Q or not.

so change the code to if letter == 'O' or letter =='Q'

Upvotes: 0

paxdiablo
paxdiablo

Reputation: 881563

if letter == 'O' or 'Q':

does not do what you think it does (see here for operator precedence), it's equivalent to:

if (letter == 'O') or ('Q'):

And, since 'Q' is a truthy value, the condition of that if statement is always true. What you would need in your case would be:

if letter == 'O' or letter == 'Q':

but a more Pythonic way would be:

if letter in ['O', 'Q']:

This also better matches your original thinking where you want to detect if the letter is any of a certain group of letters, rather than explicitly checking the letter against each and every one.

Upvotes: 1

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