Chapter 8: Problem 4

What happens if you try to use an invalid index to access a character in a string?

Short Answer

Expert verified

Answer: When attempting to access a string character using an invalid index, an "IndexError" (in Python) or a similar error specific to the programming language being used will be thrown.

Step by step solution

Identify the string and invalid index

Given any string and an index value, first, check if the index value is within the range of valid character positions in the string. An index is valid if it is between 0 (inclusive) and the length of the string (exclusive). If the index is invalid, that means trying to access a character in the string using this index value will produce an error. Example: Let's take the string "Hello" and an index value of -1 or 5. Both these index values are invalid, as the valid indices for this string are 0, 1, 2, 3, and 4.

Attempt to access the character

If an attempt is made to access a character in a string using an invalid index, the language's built-in error handling mechanism will catch the error. Typically, this would result in an "IndexError" (Python) or a similar error being thrown. Example: In Python, trying to access a character in the string "Hello" using an invalid index like -1 or 5 will result in an error: ```python string = "Hello" print(string[-1]) # This will raise an IndexError because -1 is an invalid index. print(string[5]) # This will also raise an IndexError because 5 is outside the range of valid indices for this string. ```

Using valid indices to access characters in a string

To avoid errors, always ensure that the index you use to access a string character is valid. Valid indices are integers in the range of 0 (inclusive) to the length of the string (exclusive). Example: With the string "Hello", valid indices are 0 to 4, so you can access its characters as follows: ```python string = "Hello" print(string[0]) # Output: H print(string[1]) # Output: e print(string[2]) # Output: l print(string[3]) # Output: l print(string[4]) # Output: o ``` Remember to always check the validity of indices when working with strings to avoid errors and ensure a smooth program execution.

Unlock Step-by-Step Solutions & Ace Your Exams!

Full Textbook Solutions
Get detailed explanations and key concepts
Unlimited Al creation
Al flashcards, explanations, exams and more...
Ads-free access
To over 500 millions flashcards
Money-back guarantee
We refund you if you fail your exam.

Start your free trial

Over 30 million students worldwide already upgrade their learning with Vaia!

Recommended explanations on Computer Science Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

What happens if you try to use an invalid index to access a character in a string?

Short Answer

Step by step solution

Identify the string and invalid index

Attempt to access the character

Using valid indices to access characters in a string

One App. One Place for Learning.

Most popular questions from this chapter

Recommended explanations on Computer Science Textbooks

Databases

Functional Programming

Issues in Computer Science

Computer Systems

Problem Solving Techniques

Computer Programming

Study anywhere. Anytime. Across all devices.