Typeerror String Indices Must be Integers Error in Python

We know that the TypeError string indices must be integers error occurs when we tried to find the index of iterables which includes tuples, lists, and strings. Like many other popular programming languages, strings in Python are arrays of bytes representing Unicode characters. However, Python does not have a character data type, a single character is simply a string with a length of 1. Square brackets can be used to access elements of the string. Sometimes while accessing the elements of a string we get TypeError: string indices must be integers error. In this short article, we will learn how we can solve this error using various techniques. Moreover, we will also discuss what this actually means and why we are getting it.

Solve TypeError string indices must be integers

In Python, we can get access to the elements of the strings using the indices. We need to understand that the indices in Python start from zero and then go on. If we tried to get access to the element by its name, we will get the TypeError: string indices must be integers errors.

For example, let us say we have a string and we want to access the first element: If we will try to access the element by its name as shown below, we will get an error:

# creating a string
string = 'Hello World'

# accessing the element
first_element = string['H']

Output:

As you can see, we get TypeError which means we have done a mistake in by applying different data types. And after the TypeError, the error is telling us what we have done wrong. It clearly says that we can only access the elements of a string using integers not by strings or any other elements:

If you will try to access the element using a floating element, you will again get the same error as shown below:

# creating a string
string = 'Hello World'

# accessing the element
first_element = string[1.0]

Output:

The reason for getting string indices must be integers error is again that we can only get access to the elements of the string by using integers as index values.

Using integers as index values

In Python indexing starts from zero which means the first element in a string can be accessed by specifying its index value as zero. So, to get access to the first element, we need to use 0 as the index value.

# creating a string
string = 'Hello World'

# accessing the element
first_element = string[0]

# printing 
print(first_element)

Output:

H

As you can see, we were able to get the first element from the string using an integer value as the index value.

Using the round method

If you are getting this error because the index value in your case is a floating number then you can use the round method to make it an integer value. The round method in Python will round the floating number to the nearest integer value.

Let us take an example and see how we can use the round method.

# creating a string
string = 'Hello World'

# accessing the element
first_element = string[round(1.0)]

# printing 
print(first_element)

Output:

e

As you can see, we get access to the second element of the string.

Slicing string

If you want to get access to the sub-string or small part of the string then we need to use the slicing method. In Python, we can use the slicing method to get access to the sub-part of the string.

For example, here we will print only the word “Hello” using the slicing method.

# creating a string
string = 'Hello World'

# accessing the element
first_element = string[0:5]

# printing 
print(first_element)

Output:

Hello

As you can see, we got the sub-string from the main string using the slicing method.

Using negative indexing

In Python, we can also use negative indexing to get access to the elements in the string. The negative indexing starts from -1 which represents the last element and -2 represents the second last element.

Let us now use the negative indexing to get access to the last element of the string.

# creating a string
string = 'Hello World'

# accessing the element
first_element = string[-1]

# printing 
print(first_element)

Output:

d

As you can see, we got the last element:

Using for loop

If you are trying to iterate through the string to print all the elements but getting TypeError: string indices must be integers error, then most probably you are making a mistake in the indexing again.

The following is the incorrect way to iterate through a string using for loop:

# creating a string
string = 'Hello World'

# using the for loop
for i in string:
    
    # printing 
    print(string[i])

Output:

As you can see, we get errors because we are again trying to access the elements directly. If we are using for loop, then we have to use len() to find the length of the string first as shown below:

# creating a string
string = 'Hello World'

# using the for loop
for i in range (0, len(string)):
    
    # printing 
    print(string[i])

Output:

H
e
l
l
o
 
W
o
r
l
d

As you can see, now we got access to the elements and were able to iterate through the string.

Understanding the Typeerror string indices must be integers

Let us understand the errors in Python taking Typeerror: string indices must be integers as an example. Any error in Python will have two main parts. The first will show the category of the error which in our case is the TypeError which means we are misusing some datatypes in our code. The second part of the error gives more specific information about the error and helps us to find out what kind of type error is there. In our case, it clearly says that we are using some non-integer values as string indices.

How do the indices work in Strings in Python?

In Python, the index value starts from zero and goes on. This means that the first element of the string can be accessed using the zero index value.

Also, in Python, we have negative indexing which starts from negative 1. Where -1 represents the last character in the string and -2 second last.

You can use either negative or positive indexing in Python to access the elements of a string.

Summary

In this short article, we learned how we can solve TypeError: string indices must be integers errors using various techniques. We also discuss what this error means and the reasons for getting their error. Hopefully, any of the above techniques had helped you to get rid of the error.

Related Errors

• TypeError: Unsupported Operand Type(s) for -: ‘list’ and ‘list’
• ValueError: You Must Pass a Freq Argument as Current Index has None
• TypeError: ‘module’ object is not callable [Solved]