Python TypeError

Question

So I have the code:

intex = input("Enter in a letter of text\n")
if intex == 'a' or 'b' or 'c' or 'd' or 'e' or 'f' or 'g' or 'h' or 'j' or 'k' or 'l' or 'm' or 'n' or 'o' or 'p' or 'q' or 'r':
    counter += intex
    print(counter)

By the way, all the letters are defined, I just didn't think it was neccessary to put them in,(a = 1, b= 2, etc.) but whenever I run the code, it gives me the error TypeError: unsupported operand type(s) for +=: 'int' and 'str'

I know what this error means, that i cant add a letter to a number, but is there a way to do this without the error? i tried float(), but that gave me another error! please help!

`intex == 'a' or 'b' or 'c'` What do you think this does? Can you explain this code snippet? It's unlike any Python I've ever seen. — S.Lott, Feb 20 '12 at 19:57
`counter += input('Enter in a letter of text\n') in 'abcdefghijklmnopqr'` — Steven Rumbalski, Feb 20 '12 at 20:03

score 7 · Accepted Answer · answered Feb 20 '12 at 19:53

7

The or operator does not work the way you think. The expression a or b returns a if it has a trucy truth value, and to b otherwise. You probably mean

if intex in "abcdefghijklmnopqr":
    ...

To translate the letter into an integer such that a maps to 1 etc, you can use ord():

counter += ord(intex) - ord("a") + 1

answered Feb 20 '12 at 19:53

Sven Marnach

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gives me this error TypeError: ord() expected a character, but string of length 0 found – Billjk Feb 20 '12 at 19:57
@SolomonWise: I added further information -- the answer originally only consisted of the first part or `or`. – Sven Marnach Feb 20 '12 at 20:02
3

@SolomonWise: Did you actually *try* the code? Did you follow the link to the documentation of `ord()`? – Sven Marnach Feb 20 '12 at 20:22

Uku Loskit · Answer 2 · 2012-02-20T20:11:45.203

4

if intex == 'a' or 'b' or 'c'

should instead be intex == 'a' or intex == 'b' ...

An easier way to do this would be to use the in operator. I can only assume that you want something like this to store the values somewhere.

my_list = []
if ord(intex) >= ord("a") and ord(intex) <=ord("r"):
     my_list.append(ord(intex))

Could you specify what the code should do? It looks rather strange.

edited Feb 20 '12 at 20:11

answered Feb 20 '12 at 19:54

Uku Loskit

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this gives me error ValueError: invalid literal for int() with base 10: 'a' – Billjk Feb 20 '12 at 20:02
sorry, dunno what I was thinking. what are you trying to do? your code does not make much sense. why are you adding the string to a counter? – Uku Loskit Feb 20 '12 at 20:03
i am converting letters to numbers – Billjk Feb 20 '12 at 20:03
1

The new version will error out if the user enters a string consisting of more than one character. I thought about all this before I wrote my answer -- this is why I did *not* use comparison operators, but `in`. – Sven Marnach Feb 20 '12 at 20:15
ok, sorry, the whole post has been a mess from the start. should not try to post on SO when i'm tired, made so many mistakes during so many edits. +1 to you. – Uku Loskit Feb 20 '12 at 20:17
@UkuLoskit: I've done much worse than this in some posts when I was tired. :) – Sven Marnach Feb 20 '12 at 20:22

Python TypeError

2 Answers2