Greetings! Today, you will dive into handling and manipulating strings in Kotlin, a fundamental skill across many areas of programming. Specifically, we'll explore how to identify consecutive groups of identical characters in a string. Eager to enhance your Kotlin skills? Let's get started!
In this lesson, your objective is to write a Kotlin function that accepts a string as input and identifies all consecutive groups of identical characters within it. A group is defined as a segment of text wherein the same character is repeated consecutively.
Your function should return a List of strings. Each string will consist of the repeating character and the length of its repetition, joined by a colon (:). For example, if the input string is "aaabbcccaae", your function should output: "a:3", "b:2", "c:3", "a:2", "e:1".
Remember, while processing the input string, we are interested only in alphanumeric characters (i.e., letters and digits), without differentiating the case. Non-alphanumeric characters should be ignored when forming these groups.
Ready to learn how to accomplish this task with Kotlin? Let's move forward!
When solving any problem, it's crucial to start by establishing our scope with some preliminary steps. First, we will initialize an empty MutableList to store our results. We will also declare two variables, currentGroupChar and currentGroupLength, to help us monitor the character of the current group and its consecutive sequence length.
Kotlin1// Function to find consecutive character groups in a string 2fun findGroups(inputStr: String): List<String> { 3 val groups = mutableListOf<String>() // List to store the groups of characters 4 var currentGroupChar: Char? = null // Variable to hold the current character group 5 var currentGroupLength = 0 // Variable to hold the length of the current character group 6}
With the setup in place, we can now proceed to process the input string. We'll use a loop to examine each character. At every step, we'll check if the character is alphanumeric, as that is our primary interest.
Kotlin1// Function to find consecutive character groups in a string 2fun findGroups(inputStr: String): List<String> { 3 val groups = mutableListOf<String>() // List to store the groups of characters 4 var currentGroupChar: Char? = null // Variable to hold the current character group 5 var currentGroupLength = 0 // Variable to hold the length of the current character group 6 7 for (c in inputStr) { 8 if (c.isLetterOrDigit()) { // Check if the character is alphanumeric 9 // Processing logic will be added here 10 } 11 } 12}
As the loop executes, if a character is the same as currentGroupChar, it implies that the group is continuing, and we simply increment currentGroupLength. However, if the character differs from currentGroupChar, it signals the start of a new group.
At the start of a new group, we will add the string formed by using Kotlin's string templates with currentGroupChar and currentGroupLength to groups, then update currentGroupChar and currentGroupLength to the new character and 1, respectively.
Kotlin1// Function to find consecutive character groups in a string 2fun findGroups(inputStr: String): List<String> { 3 val groups = mutableListOf<String>() // List to store the groups of characters 4 var currentGroupChar: Char? = null // Variable to hold the current character group 5 var currentGroupLength = 0 // Variable to hold the length of the current character group 6 7 for (c in inputStr) { 8 if (c.isLetterOrDigit()) { // Check if the character is alphanumeric 9 if (c == currentGroupChar) { // If the character is part of the current group 10 currentGroupLength += 1 // Increment the length of the current group 11 } else { // If the character starts a new group 12 currentGroupChar?.let { 13 groups.add("$it:$currentGroupLength") // Add the group to the list 14 } 15 currentGroupChar = c // Update the current character to the new group 16 currentGroupLength = 1 // Reset the length for the new group 17 } 18 } 19 } 20}
After the loop ends, ensure any leftover group not yet added to groups is accounted for. This final step is necessary because a group is only added to groups when we identify a new group. Perform a final check on currentGroupChar and, if needed, add it to groups.
Kotlin1// Function to find consecutive character groups in a string 2fun findGroups(inputStr: String): List<String> { 3 val groups = mutableListOf<String>() // List to store the groups of characters 4 var currentGroupChar: Char? = null // Variable to hold the current character group 5 var currentGroupLength = 0 // Variable to hold the length of the current character group 6 7 for (c in inputStr) { 8 if (c.isLetterOrDigit()) { // Check if the character is alphanumeric 9 if (c == currentGroupChar) { // If the character is part of the current group 10 currentGroupLength += 1 // Increment the length of the current group 11 } else { // If the character starts a new group 12 currentGroupChar?.let { 13 groups.add("$it:$currentGroupLength") // Add the group to the list 14 } 15 currentGroupChar = c // Update the current character to the new group 16 currentGroupLength = 1 // Reset the length for the new group 17 } 18 } 19 } 20 currentGroupChar?.let { 21 groups.add("$it:$currentGroupLength") // Add the last group if it exists 22 } 23 return groups // Return the list of groups 24} 25 26// Example usage 27fun main() { 28 val input = "aaabbcccaae" 29 val result = findGroups(input) 30 for (group in result) { 31 println(group) 32 } 33 // Output: 34 // a:3 35 // b:2 36 // c:3 37 // a:2 38 // e:1 39}
Congratulations! You have now learned how to identify consecutive groups of characters in a string using Kotlin. This skill is valuable in text analysis or when preprocessing data for further applications. To solidify your understanding, practice solving similar problems in Kotlin. Remember, proficiency comes from persistence and consistent practice. Now, let's continue to explore the possibilities with Kotlin!