我不断收到错误消息：TypeError: tuple indices must be integers or slice, not str

Question

So I've looked all over the place and cant seem to get an answer that I understand. I am trying to implement a piece of code where Python looks at a text file, gets a line, and looks for a dictionary with a corresponding name. Here is my code so far:

f = open("data.txt", "r")
  
content = f.readlines()

icecream = {
    "fat": 80,
    "carbohydrates": 50,
    "protein": 650,
    "calories": 45,
    "cholesterol": 50,
    "sodium": 50,
    "name": "Icecream"
}
bigmac = {
    "fat": 29,
    "carbohydrates": 45,
    "protein": 25,
    "sodium": 1040,
    "cholesterol": 75,
    "calories": 540,
    "name": "Big Mac"
  }
whopper = {
    "fat": 47,
    "carbohydrates": 53,
    "protein": 33,
    "sodium": 1410,
    "cholesterol": 100,
    "calories": 760,
    "name": "Whopper"
  }
menu = [
  bigmac,
  whopper,
  icecream
]

sea = content[0]
for line in enumerate(menu):
  if sea.lower() in line['name'].lower():
    print (line['name'])

I keep getting the error TypeError: tuple indices must be integers or slices, not str and I don't understand why. Could someone help me fix my code and possibly get my 2 brain-cells to understand why this error comes up?

Answer 1

enumerate() returns a tuple of index and element. Eg:

>>> for item in enumerate(["a", "b", "c"]):
>>>    print(item)
(0, "a")
(0, "b")
(0, "c")

So when you enumerate over your menu list, your item is not this dict, but tuple of index and dict. If you don't need index of element, use:

for line in menu:
    if sea.lower() in line['name'].lower():
        print (line['name'])

If you need index, use:

for i, line in enumerate(menu):
    if sea.lower() in line['name'].lower():
        print (i, line['name'])

Answer 2

Update your code to:

for line in menu:
  if sea.lower() in line['name'].lower():
    print (line['name'])

"enumerate" is useless with menu that is already an array

Answer 3

Your error arises when calling line['name'] , as line is a tuple produced by the enumerate call:

(0, {'fat': 29, 'carbohydrates': 45, 'protein': 25, 'sodium': 1040, 'cholesterol': 75, 'calories': 540, 'name': 'Big Mac'})
(1, {'fat': 47, 'carbohydrates': 53, 'protein': 33, 'sodium': 1410, 'cholesterol': 100, 'calories': 760, 'name': 'Whopper'})
(2, {'fat': 80, 'carbohydrates': 50, 'protein': 650, 'calories': 45, 'cholesterol': 50, 'sodium': 50, 'name': 'Icecream'})

As such, it will need a integer in order to know which of menu 's items to call.

Answer 4

enumerate(menu) returns a "tuple" and the way you were accessing it as a dictionary has caused this error. Also, use splitlines to handle if there is any new-line characters in the read string.

So, change the code as below without enumerate.

sea = content.splitlines()[0]
for line in menu:
  if sea.lower() in line['name'].lower():
    print (line['name'])

This depends on how the input file data is. Share us how the input file looks like, if this is not working.