Last month, I spent three days fighting with regular expressions.
I had a pile of unstructured product descriptions from various suppliers—some with prices hidden in paragraphs, others with specs scattered across bullet points. My job was to normalize them into a clean JSON structure: { name, price, specs, description }.
It started simple. A few regex patterns. \$\d+\.\d{2} for prices. (?<=Brand:)\w+ for brands. Then the edge cases hit me like a freight train.
The Regex Nightmare
The first supplier used "$12.99" format. The second used "USD 12.99". One even wrote "costs around twelve dollars and ninety nine cents". My regex grew into a monster spanning 40 lines, with lookaheads, groups, and conditional statements. It worked for the first 20 products. Then I ran it on the full dataset (10,000 records).
