✨ 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.

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↺ 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.

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⚖️ 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.

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💡 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.

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🛠 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.

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🧵 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.