word_counter

📊 Word Counter CLI

A CLI tool that analyzes text files and provides statistics including word frequency analysis.

🎯 Learning Objectives

• File I/O: Reading files from disk
• HashMap: Using collections for frequency counting
• Iterators: Processing text with iterator methods
• String Operations: Splitting, trimming, case conversion
• Path Handling: Working with std::path::Path

📈 Features

• Line count
• Word count
• Character count
• Top 5 most frequent words

🚀 Running the Program

cargo run

Then enter the path to a text file when prompted.

📝 Example Output

Enter file path:
> text.txt

Lines: 3
Words: 89
Chars: 571

Top 5 words:
the: 8
of: 6
code: 5
to: 4
a: 4

🔑 Key Concepts Demonstrated

HashMap for Frequency Counting

let mut top_words: HashMap<String, usize> = HashMap::new();

for word in &words {
    let word = word.to_lowercase();
    *top_words.entry(word).or_insert(0) += 1;
}

Sorting by Frequency

let mut top_vec: Vec<(String, usize)> = top_words.into_iter().collect();
top_vec.sort_by(|a, b| b.1.cmp(&a.1));

for (word, count) in top_vec.iter().take(5) {
    println!("{}: {}", word, count);
}

File Reading with Error Handling

fn read_file_content(path: &Path) -> String {
    match fs::read_to_string(path) {
        Ok(content) => content,
        Err(err) => {
            println!("err: {}", err);
            panic!("Failed!!")
        }
    }
}

Iterator-Based Processing

let words = content.split_whitespace().collect::<Vec<&str>>();
let lines = content.lines().count();
let chars = content.chars().collect::<Vec<char>>().len();

💡 What I Learned

1. Collections: Using HashMap for counting and aggregation
2. Ownership with Collections: Understanding how data moves between HashMap and Vec
3. Iterator Adapters: Chaining .iter(), .take(), .collect()
4. Entry API: Using .entry().or_insert() for elegant counting
5. Path Types: Difference between &str, String, and &Path

🔄 Possible Improvements

• Better error handling with Result instead of panic!
• Configurable top N words
• Ignore common stop words (the, a, an, etc.)
• Support multiple file formats
• Export results to JSON/CSV
• Add unit tests

📚 Relevant Rust Book Chapters

• Chapter 8: Common Collections
• Chapter 12: I/O Project

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Status: ✅ Completed | Difficulty: Beginner