Скачать или смотреть Converting a User Input String to a List of Integers in Kotlin

Learn how to convert a user-input string to a list of integers in Kotlin. This guide offers simple solutions to help you avoid common Kotlin pitfalls.
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This video is based on the question https://stackoverflow.com/q/67775846/ asked by the user 'Serdar Çivi' ( https://stackoverflow.com/u/15361535/ ) and on the answer https://stackoverflow.com/a/67776519/ provided by the user 'Joffrey' ( https://stackoverflow.com/u/1540818/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Converting a User Input String to a List of Integers in Kotlin: A Step-by-Step Guide

Are you struggling with how to convert a string of digits into a list of integers in Kotlin? Whether you're new to the language or just need a bit of guidance, you've come to the right place! This post will walk you through a common issue encountered when attempting to convert a string input like "12345" into a list of [1, 2, 3, 4, 5]. We’ll also provide some practical solutions that will help you avoid the notorious NumberFormatException and ensure smooth conversions.

Understanding the Problem

When you attempt to convert a string input into a list of integers in Kotlin, you may run into some unexpected errors or behavior. For example, let's consider the following code snippet you might use:

[[See Video to Reveal this Text or Code Snippet]]

Common Errors

Here are a few issues you might encounter:

NumberFormatException: This occurs when something is wrong with the number formats being processed, like trying to convert an empty string or incorrectly mapped values.

Incomplete Lists: Upon modifying delimiters, you may get results like [ , 1, 2, 3, 4, 5] instead of the desired list.

Breaking Down the Solution

Fortunately, there are easy ways to perform the conversion correctly depending on the version of Kotlin you are using. Let's explore various solutions based on the available Kotlin versions.

For Kotlin Version = 1.6

If you are using Kotlin version 1.6 or higher, you can use the readln() function along with map as follows:

[[See Video to Reveal this Text or Code Snippet]]

For Kotlin Version = 1.5 but 1.6

For those with Kotlin versions that range from 1.5 up to (but not including) 1.6:

[[See Video to Reveal this Text or Code Snippet]]

For Kotlin Version 1.5

If you are working with an older version of Kotlin (below 1.5), the solution can be implemented this way:

[[See Video to Reveal this Text or Code Snippet]]

Explanation

Now, you may wonder why we use "$it".toInt() in older versions. This is necessary because Char.toInt() would return the ASCII code of the character instead of its actual integer value. By converting the character to a string first, String.toInt() will accurately parse it in decimal format. The introduction of Char.digitToInt() in Kotlin 1.5 provides a cleaner and more efficient way to get the integer value directly.

Conclusion

In summary, converting a string of digits into a list of integers in Kotlin doesn't have to be a daunting task. With the provided solutions based on your Kotlin version, you can easily avoid the common pitfalls and enjoy smooth programming experiences.

Key Takeaways:

Use digitToInt() for a direct conversion from a character to its integer value.

Be aware of the Kotlin version you are using to select the right method.

Always handle potential exceptions, like missing inputs, gracefully.

Now, grab your Kotlin IDE and give it a try! Happy coding!