Which error occurs when an index is not found in a sequence?

• A. IndexError
• B. KeyError
• C. ValueError
• D. TypeError

Answer: (A)

The error that occurs when an index is not found in a sequence is called IndexError. This specific error is raised when you attempt to access an index that is outside the bounds of the sequence, such as a list or a tuple. For example, if you try to access the fifth element of a list that contains only three elements, Python will raise an IndexError, indicating that the index you are trying to access does not exist in that sequence.

In contrast, other types of errors relate to different issues. A KeyError occurs when you attempt to access a dictionary with a key that does not exist. A ValueError is raised when an operation or function receives an argument that has the right type but an inappropriate value. Lastly, a TypeError happens when an operation or function is applied to an object of inappropriate type, such as trying to add a string and an integer together.

Understanding the context of these errors helps in debugging and ensures that index operations on sequences are handled properly.