TypeError String Indices Must be Integers Python Error [Solved]

If you try to access values from a dictionary or iterable object using the string value instead of the integer value then you will receive the following error message:

TypeError: string indices must be integers

In this article, I will show you examples of why you might receive this error message and how to fix it.

How to Access Values from a List in Python

In this example, we have the following list of musical instruments:

instruments = ['flute', 'trumpet', 'oboe', 'percussion', 'guitar']

If we wanted to access the third instrument in the list, we would use the numerical index value of 2:

instruments[2]

The following line of code would correctly print out the result of oboe:

instruments = ['flute', 'trumpet', 'oboe', 'percussion', 'guitar']
print(instruments[2])

If I tried to access that same list but instead used the string index of 'oboe', then it would result in an error message:

instruments = ['flute', 'trumpet', 'oboe', 'percussion', 'guitar']
print(instruments['oboe'])

If you encounter this error message, double check to make sure you are using the numerical index value to access elements instead of a string value.

How to Access Values from a Dictionary in Python

Let's modify our earlier example to create a dictionary of instruments and quantities.

instruments = {
    'flute': 2,
    'trumpet': 5,
    'oboe': 1,
    'percussion': 4,
    'guitar': 9
}

If we wanted to print out all of the values from our instruments dictionary, then we can use a loop with the .values() method.

for quantity in instruments.values():
    print(quantity)

If we removed the .values() method and tried to access the values using string indices, then we would receive the follow error message:

for quantity in instruments:
    print(quantity['flute'])
    print(quantity['trumpet'])
    print(quantity['oboe'])
    print(quantity['percussion'])
    print(quantity['guitar'])

If you print out quantity, then you will see that it is a string.

for quantity in instruments:
    print(quantity)

If you tried to write quantity['flute'], then it translates to 'flute'['flute'] which does not make sense in Python.

The way to resolve this would be to reference our instruments dictionary instead of using quantity.

The following refactored code would produce the correct results:

instruments = {
    'flute': 2,
    'trumpet': 5,
    'oboe': 1,
    'percussion': 4,
    'guitar': 9
}

print(instruments['flute'])
print(instruments['trumpet'])
print(instruments['oboe'])
print(instruments['percussion'])
print(instruments['guitar'])

I hope you enjoyed this article and best of luck on your Python journey.