I keep getting an error on the line with the #. I've tried putting "" around each symbol, all the symbols together, and put the symbols in ()

Question

I keep getting an error on the line with the #. I’ve tried putting "" around each symbol, all the symbols together, and put the symbols in ().

def main():

  name = input("Enter a reader's name: ")
  symbol = input("Enter a symbol: ")
  rating = input("Enter a rating: ")

  if name not in 'ratings.txt':
    print("No such reader " + name)
    print("bye!")
    return
  #if symbol not >,<,=:
    print("please use >,<,=")
    return
  if rating not -5,-3,0,1,3:
    print("please use -5,-3,0,1,3")
    return
  if name = []:
    print('no books found')
    return

Asked By: cdj

||

Source

Answer 1

You can use the not in construct to check if an item is not in a list/tuple/other container. Thus, you can do this:

item = "foo"
print(item not in ["foo", "bar", "baz"]) # False
print(item not in ["ham", "egg", "pan"]) # True

This works for numbers too. However, using sets (with curly braces) is more efficient if all you’re doing is testing if an item is in the container. Also, I see your code has

if name = []:

When testing for equality in an if statment, use the equals operator ==. Thus your code will be:

  name = input("Enter a reader's name: ")
  symbol = input("Enter a symbol: ")
  rating = input("Enter a rating: ")

  if name not in 'ratings.txt':
    print("No such reader " + name)
    print("bye!")
    return
  if symbol not in {">", "<", "="}:
    print("please use >,<,=")
    return
  if rating not in {-5, -3, 0, 1, 3}:
    print("please use -5,-3,0,1,3")
    return
  if name == []:
    print('no books found')
    return

Finally, the line

if name not in "ratings.txt":

does not check if name is in the contents of the file ratings.txt, but rather if it is a substring of that filename. For checking the file contents, you can try this question.

Answered By: pigrammer

I keep getting an error on the line with the #. I've tried putting "" around each symbol, all the symbols together, and put the symbols in ()

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