Remove All Occurrences Except Last

When working with strings in programming, it's common to encounter scenarios where you need to manipulate the text to fit specific requirements. One such requirement could be removing all occurrences of a particular substring except for the last one. In this article, we'll explore a practical approach to achieve this in your code effectively.

To start off, let's consider a simple example in JavaScript to demonstrate this concept. Suppose we have a string that contains multiple occurrences of a certain word, and we want to remove all instances of the word except for the last occurrence. Here's how you can do this using JavaScript:

function removeOccurrencesExceptLast(inputString, word) {
  const lastIndex = inputString.lastIndexOf(word);
  const stringWithLastOccurrence = inputString.slice(0, lastIndex) + inputString.slice(lastIndex).replace(new RegExp(word, 'g'), '');
  
  return stringWithLastOccurrence;
}

const input = "apple orange banana apple orange apple";
const wordToRemove = "apple";

const result = removeOccurrencesExceptLast(input, wordToRemove);
console.log(result); // Output: "apple orange banana orange apple"

In this code snippet, the `removeOccurrencesExceptLast` function takes two parameters: `inputString`, the original string, and `word`, the word you want to remove all occurrences of except the last one. It then finds the index of the last occurrence of the word using `lastIndexOf`. Next, it constructs a new string by combining the substring before the last occurrence with the substring after the last occurrence where we removed all other occurrences of the word using `replace`.

The use of `lastIndexOf` allows us to pinpoint the position of the last occurrence of the word within the string, ensuring that we retain the intended structure of the text while removing unwanted duplicates.

This method is not limited to JavaScript; you can apply a similar logic in other programming languages such as Python, Java, or C++. By understanding the underlying logic of finding the last occurrence of a substring, you can adapt and implement this functionality in the language of your choice.

In conclusion, the ability to remove all occurrences of a particular substring except for the last one is a handy technique to have in your programming arsenal. Whether you're handling text processing tasks, data manipulation, or any other scenario that involves string manipulation, this approach can help you achieve the desired output efficiently.

By following the steps outlined in this article, you can enhance your code's readability and maintainability while addressing specific requirements related to string manipulation. Practice implementing this technique in your projects to become more proficient in handling similar tasks effectively.