Fix Typeerror: list indices must be integers or slices, not str

Fix Typeerror: list indices must be integers or slices, not str

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Introduction

In Python, lists are a type of data structure that can hold a collection of items. These items can be accessed using their index, which is an integer value. However, if you try to access a list item using a string value instead of an integer, you will encounter the "TypeError: list indices must be integers or slices, not str" error.

Typeerror: list indices must be integers or slices, not str Cause

This example will raise the "TypeError: list indices must be integers or slices, not str" error. The code is trying to access the element at the index "two" of the list, which is a string value. However, the index of a list must be an integer. Therefore, python will raise this error.

Example

my_list = [1, 2, 3, 4]
print(my_list["two"])

Output:

TypeError: list indices must be integers or slices, not str
TypeError: list indices must be integers or slices, not str.

Solution

To fix this error, you need to use an integer value to access the item in the list. You can use the index() method to find the index of a specific item in the list.

Solution 1

In this example, the code is using the index() method to find the index of the element 3 in the list. The index() method returns the index of the first occurrence of the given item in the list. The variable "index" will be assigned the value 2 (the index of the element 3 in the list). Then, the element at that index is accessed using my_list[index], and the output will be 3.

my_list = [1, 2, 3, 4]
index = my_list.index(3)
print(my_list[index])

Output:

3

Solution 2

This example is similar to the previous one, but it uses a list of strings. The code is using the index() method to find the index of the element "banana" in the list. The variable "index" will be assigned the value 1 (the index of the element "banana" in the list). Then, the element at that index is accessed using my_list[index], and the output will be "banana".

my_list = ["apple", "banana", "cherry"]
index = my_list.index("banana")
print(my_list[index])

Output:

banana

Note

It's also important to note that, you can use negative integers to index a list from the end, starting with -1 for the last item.

Solution 3

In this example, the code is using a negative integer to access an element in the list. Negative integers start counting from the end of the list, with -1 being the last item in the list. The code is accessing the last item in the list my_list[-1] the output will be "cherry".

my_list = ["apple", "banana", "cherry"]
print(my_list[-1])

Output:

cherry

See also: How to fix "TypeError: builtin_function_or_method object is not subscriptable" in Python?

Conclusion

In conclusion, the "TypeError: list indices must be integers or slices, not str" error occurs in Python when you try to access a list item using a string value instead of an integer. To fix this error, you need to use an integer value to access the item in the list, you can use the index() method to find the index of a specific item in the list, or use negative integers to index a list from the end.

FAQ

What is the "TypeError: list indices must be integers or slices, not str" error in Python?

This error occurs when you try to access a list item using a string value instead of an integer. Python lists are a type of data structure that can hold a collection of items, and these items can be accessed using their index, which is an integer value. If you try to access a list item using a string value, Python will raise this error.

How can I fix the "TypeError: list indices must be integers or slices, not str" error in Python?

To fix this error, you need to use an integer value to access the item in the list. You can use the index() method to find the index of a specific item in the list. For example, my_list.index(3) will return the index of the element 3 in the list. You can then use this index value to access the item, like my_list[index].

Can I use negative integers to index a list in Python?

Yes, you can use negative integers to index a list in Python. Negative integers start counting from the end of the list, with -1 being the last item in the list. For example, you can use my_list[-1] to access the last item in the list. This can be useful if you want to access the last item in the list without knowing its index value.