'AttributeError: 'tuple' 对象没有属性 'lower'' - 为什么 '.lower()' 方法在 Python 中不起作用？

Question

I am currently learning python and doing the exercises in the module. I have learned previously how to remove any case letter in the string, so it will be easier for the user to use it later on. But it seems like when I applied the ' XXX.lower() ' method to my code, it doesnt work. It works just fine without the '.lower()' method but I really want to know why it doest work ? Here's my code :

# bird names list
bird_names = ("Parrot", "Owl", "Pigeon", "Crow", "Peacock", "Hen")

# bird guess
bird_guess = input("Enter a bird name (Guess 1): ")

# nested conditions starts here
if bird_guess.lower() in bird_names.lower():
  print("Yes, 1st try!")
else:
  bird_guess = input("Enter a bird name (Guess 2): ")
  if bird_guess.lower() in bird_names.lower():
    print("Yes, 2nd try!")
  else:
    bird_guess = input("Enter a bird name (Guess 3): ")
    if bird_guess.lower() in bird_names.lower():
      print("Yes, 3rd try!")
    else:
      print("Sorry, out of tries.")

Answer 1

bird_names is a tuple, .lower() is supposed to be called on a string. You might want to consider something like

bird_names = ("Parrot", "Owl", "Pigeon", "Crow", "Peacock", "Hen")
bird_names = [name.lower() for name in bird_names]

and then you can use

if bird_guess.lower() in bird_names:
    ....

Answer 2

Because bird names is a tuple object not a string. In order for this to work what you can do is updating or overwriting the existing tuple with a list comprehension or generating a new variable. Instead of bird_names.lower() you can use the new list or tuple in the conditions.

bird_names_lower = [bird.lower() for bird in bird_names]

Answer 3

• bird_names is a list object
• .lower() is a string function

maybe something like this can help you:

if bird_guess.lower() in [word.lower() for word in bird_names]:

Answer 4

You are trying to use .lower() , which is a string method, on the tuple bird_names . If you want the strings in bird_names to be lower case, either hard code them as lower case or modify them with something like a tuple comprehension.

bird_names = tuple(x.lower() for x in bird_names)

Then you can test bird_guess.lower() for membership in bird_names

if bird_guess.lower() in bird_names: