✨ The Art of Lossless Data Compression in Ruby

April 24, 2025

In a world overflowing with data, compression isn’t just a matter of saving space—it’s about efficiency, speed, and clean design. That’s where lossless data compression stands out: perfect reconstruction of original data, with zero information loss.

Recently, I explored a classic algorithm—Run-Length Encoding (RLE)—and implemented it in pure Ruby. It’s a great way to revisit fundamental ideas that power modern compression formats.

Want to reduce file sizes, optimize your system, or explore efficient data handling in Ruby?

Whether it’s compressing strings, optimizing processes, or solving tricky performance problems—I’d love to help.

↺ What is Run-Length Encoding (RLE)?

Run-Length Encoding is one of the simplest lossless algorithms. It compresses data by replacing repeated elements with a single value and a count.

Say you have this string:

AAAAABBCCCCDDDDDD 

It becomes:

A5B2C4D6 

You just reduced 17 characters to 8, without losing any information. And reversing the process gives you back the original string—bit for bit.

RLE in Ruby

Here’s a simple module that does both compression and decompression in Ruby:

module Compression
  class RLE
    def self.encode(input)
      input.gsub(/(.)\1*/) { |match| "#{match[0]}#{match.length}" }
    end

    def self.decode(input)
      input.scan(/(.)(\d+)/).map { |char, count| char * count.to_i }.join
    end
  end
end 

Example:

compressed = Compression::RLE.encode("AAAAABBCCCCDDDDDD")
# => "A5B2C4D6"

original = Compression::RLE.decode("A5B2C4D6")
# => "AAAAABBCCCCDDDDDD" 

It’s that clean.

Why Try This?

Even in everyday Ruby projects, compression can help:

• Reduce memory usage
• Optimize storage
• Speed up data processing
• Teach foundational algorithmic thinking

Plus, writing your own compression/decompression tool is a rewarding coding challenge.

Bonus: Zlib for Production Compression

Ruby has a built-in Zlib module that supports more advanced algorithms like GZIP and Deflate:

compressed = Zlib::Deflate.deflate("your data here")
original = Zlib::Inflate.inflate(compressed) 

Perfect for compressing large strings, files, or logs.

Final Thoughts

Compression is more than a performance trick—it’s an art. And with Ruby, exploring these concepts is not only approachable, but fun. Whether you’re building tools or just geeking out on algorithms, it’s a great area to explore.

Want to go deeper into compression algorithms in Ruby or build something together? I’d love to chat.