TypeError: list indices must be integers or slices, not dict

TypeError: list indices must be integers or slices, not dict #

The Python "TypeError: list indices must be integers or slices, not dict" occurs when we use a dictionary to access a list at a specific index. To solve the error, use an integer or a slice for list indexes, e.g. my_list[0].

Here is an example of how the error occurs.

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my_dict = {'name': 'Alice', 'age': 30}

my_list = ['a', 'b', 'c']

# ⛔️ TypeError: list indices must be integers or slices, not dict
result = my_list[my_dict]

The error is caused because we are using a dictionary as a list index.

If you are iterating over a list of dictionaries, make sure to access key-value pairs of the dictionary on each iteration.

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my_list = [
    {'id': 1, 'name': 'Alice'},
    {'id': 2, 'name': 'Bob'},
    {'id': 3, 'name': 'Carl'},
]

for entry in my_list:
    print(entry['id'])
    print(entry['name'])

We used a for loop to iterate over a list of dictionaries.

You can use an index to access a specific dictionary in the list and then access the specific key of the dictionary.

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my_list = [
    {'id': 1, 'name': 'Alice'},
    {'id': 2, 'name': 'Bob'},
    {'id': 3, 'name': 'Carl'},
]

result = my_list[0]['name']
print(result)  # 👉️ 'Alice'

If you have a dictionary with a list value, access the specific key before accessing an index.

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my_dict = {
    'fruits': ['apple', 'banana', 'kiwi']
}

result = my_dict['fruits'][0]
print(result)  # 👉️ 'apple'

If you need to iterate over a dictionary, use the dict.items() method.

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my_dict = {'name': 'Alice', 'age': 30}

for key, value in my_dict.items():
    print(key, value)  # 👉️ name Alice, age 30

The dict.items method returns a new view of the dictionary's items ((key, value) pairs).

If you need to get a slice of a list, use a colon to separate the start and end indices.

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my_list = ['a', 'b', 'c', 'd', 'e']

print(my_list[0:3])  # 👉️ ['a', 'b', 'c']

print(my_list[3:])  # 👉️ ['d', 'e']

The start index is inclusive, whereas the end index is exclusive (up to, but not including).

If you aren't sure what type of object a variable stores, use the type() class.

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my_dict = {'name': 'Alice', 'age': 30}

print(type(my_dict))  # 👉️ <class 'dict'>
print(isinstance(my_dict, dict))  # 👉️ True

my_list = ['a', 'b', 'c']

print(type(my_list))  # 👉️ <class 'list'>
print(isinstance(my_list, list))  # 👉️ True

The type class returns the type of an object.

The isinstance function returns True if the passed in object is an instance or a subclass of the passed in class.

Conclusion #

The Python "TypeError: list indices must be integers or slices, not dict" occurs when we use a dictionary to access a list at a specific index. To solve the error, use an integer or a slice for list indexes, e.g. my_list[0].