Greetings! Today, you will delve into handling and manipulating strings in JavaScript, a piece of fundamental knowledge in many areas of programming. Specifically, we'll learn how to identify consecutive groups of identical characters in a string. Intrigued to enhance your skills? Without further ado, let's proceed!
In this lesson, your objective is to write a JavaScript 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 the text wherein the same character is repeated consecutively.
Your function should return an array 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"].
Bear in mind that, while processing the input string, we are interested only in alphanumeric characters (i.e., alphabets and digits). Other characters present will not factor into the formation of these groups.
Ready to discover how to accomplish this task? Let's set forth!
When aiming to solve a problem, it's always crucial to first establish our scope by taking preliminary steps. First, we will initialize an empty array to store our results. We will also declare two variables, currentGroupChar and currentGroupLength, which will help us monitor the character of the current group and the length of its consecutive sequence.
JavaScript1function findGroups(s) { 2 let groups = []; // Array to store the groups of characters 3 let currentGroupChar = ''; // Variable to hold the current character group 4 let currentGroupLength = 0; // Variable to hold the length of the current character group 5}
With the setup in place, we are now ready for the main task: processing the input string. For this, we'll create a loop to examine each character. At every step, the character is checked to see if it is alphanumeric as that is our primary interest.
JavaScript1function findGroups(s) { 2 let groups = []; // Array to store the groups of characters 3 let currentGroupChar = ''; // Variable to hold the current character group 4 let currentGroupLength = 0; // Variable to hold the length of the current character group 5 6 for (let i = 0; i < s.length; i++) { 7 let c = s[i]; 8 if (/[a-zA-Z0-9]/.test(c)) { // Check if the character is alphanumeric 9 } 10 } 11}
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 concatenating currentGroupChar and currentGroupLength with a colon (:) to groups, and then update currentGroupChar and currentGroupLength with the new character and 1, respectively.
JavaScript1function findGroups(s) { 2 let groups = []; // Array to store the groups of characters 3 let currentGroupChar = ''; // Variable to hold the current character group 4 let currentGroupLength = 0; // Variable to hold the length of the current character group 5 6 for (let i = 0; i < s.length; i++) { 7 let c = s[i]; 8 if (/[a-zA-Z0-9]/.test(c)) { // 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 if (currentGroupChar !== '') { // Add the previous group to groups if it exists 13 groups.push(currentGroupChar + ":" + currentGroupLength); 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, it's important to acknowledge any leftover group that may not yet be added to groups. This can happen because a group is only added to groups when we identify a new group. To ensure we don't miss any groups, we perform a final check on currentGroupChar and, if needed, add it to groups.
JavaScript1function findGroups(s) { 2 let groups = []; // Array to store the groups of characters 3 let currentGroupChar = ''; // Variable to hold the current character group 4 let currentGroupLength = 0; // Variable to hold the length of the current character group 5 6 for (let i = 0; i < s.length; i++) { 7 let c = s[i]; 8 if (/[a-zA-Z0-9]/.test(c)) { // 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 if (currentGroupChar !== '') { // Add the previous group to groups if it exists 13 groups.push(currentGroupChar + ":" + currentGroupLength); 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 if (currentGroupChar !== '') { // Add the last group if it exists 21 groups.push(currentGroupChar + ":" + currentGroupLength); 22 } 23 return groups; // Return the array of groups 24} 25 26// Example usage 27let input = "aaabbcccaae"; 28let result = findGroups(input); 29for (let group of result) { 30 console.log(group); 31} 32// Output: 33// "a:3" 34// "b:2" 35// "c:3" 36// "a:2" 37// "e:1"
Congratulations! You have now learned how to identify consecutive groups of characters in a string using JavaScript. This skill can come in handy when analyzing text-related problems or even when preprocessing data for various applications. To improve your grasp of the subject, you should practice similar problems. Always remember, proficiency comes through persistence and consistent effort. Now, it's time to get started with those strings!