feat: Add R program to count unique letters in a string #160
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Pull Request Overview
This PR adds a new R program for counting unique letters in a string and refactors an existing cocktail sort implementation to follow consistent naming conventions. The changes standardize the codebase to use dot notation for variable and function names throughout.
- Adds a new interactive string manipulation program that counts unique letter occurrences
- Refactors the cocktail sort algorithm to use consistent dot notation naming
- Simplifies code structure and removes redundant comments in the sorting algorithm
Reviewed Changes
Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.
| File | Description |
|---|---|
| string_manipulation/unique.letters.count.R | New R script that prompts for user input and counts unique letters in cleaned strings |
| sorting_algorithms/cocktail_sort.r | Refactored to use dot notation naming and simplified code structure |
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| input.string <- readline(prompt = "Enter a string: ") | ||
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| # Convert to lowercase and remove non-letter characters | ||
| clean.string <- tolower(gsub("[^a-z]", "", input.string)) |
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The regex pattern [^a-z] will remove uppercase letters before tolower() is applied. This should be [^a-zA-Z] to preserve all letters before converting to lowercase, or the order should be reversed to apply tolower() first.
| clean.string <- tolower(gsub("[^a-z]", "", input.string)) | |
| clean.string <- tolower(gsub("[^a-zA-Z]", "", input.string)) |
| unique.letters <- unique(letters.vec) | ||
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| # Count occurrences of each unique letter | ||
| letter.counts <- table(letters.vec) |
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The table() function is called on letters.vec but only values from unique.letters are accessed. This creates unnecessary computation for letters that won't be displayed. Consider using letter.counts <- table(letters.vec)[unique.letters] or iterating directly over the table results.
| letter.counts <- table(letters.vec) | |
| letter.counts <- table(letters.vec)[unique.letters] |
| # Display results | ||
| cat("Unique letters and their counts:\n") | ||
| for (letter in unique.letters) { | ||
| cat(letter, ":", letter.counts[letter], "\n") |
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The table() function is called on letters.vec but only values from unique.letters are accessed. This creates unnecessary computation for letters that won't be displayed. Consider using letter.counts <- table(letters.vec)[unique.letters] or iterating directly over the table results.
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Please check comments |
2 participants
This PR adds a new R script
unique.letters.count.Rthat:Variable names use dots (.) instead of underscores to follow the naming style preference.
Example:
Input: "Hello World!"
Output:
h : 1
e : 1
l : 3
o : 2
w : 1
r : 1
d : 1