Python - sys.stdin.readline() - library

Question

import sys

lijst_salades = {'Eiersalade' : 5.99,
                 'Paprikasalade' : 6.05,
                 'truffelsalade': 3.99
                 }

input = (sys.stdin.readline())
print(lijst_salades[input])

it gives me an error

Traceback (most recent call last): File "C:/some/random/dir/right/here/progr.py", line 9, in print(lijst_salades[input]) KeyError: 'truffelsalade\n'

Can someone explain what is did wrong? If I use print(lijst_salades['Eiersalade'] it works fine.

Answer 1

The problem is that you read the \n char with the input passed, as the error state:

KeyError: 'truffelsalade\n'

You should fix the code to:

import sys

lijst_salades = {'Eiersalade' : 5.99,
                 'Paprikasalade' : 6.05,
                 'truffelsalade': 3.99
                 }

input = (sys.stdin.readline()).rstrip()
print(lijst_salades[input])

Also, it is advised to add a testing to the input, because if the key doesn't exist it will also raise an error of type KeyError.

Edit

You can read about escape characters int the following links:

https://linuxconfig.org/list-of-python-escape-sequence-characters-with-examples

https://docs.python.org/2.0/ref/strings.html