Ruby by Example

Chapter Recap

What was new in this chapter?

• Exponentiation in Ruby

• Returning nil when a method’s operation is not possible

• More recursion and exit conditions

• Modules and Inheritance

• Hash.merge

• Class Variables

• Array.detect (“find first”)

• Subtracting Hashes

• Exiting the entire script with fail

• begin—rescue—end

• Downloading with open-uri

• Parsing XML files with regular expressions

• Writing to YAML files with YAML.dump

• Reading from YAML files with YAML.load

It’s almost as if this chapter weren’t really about numbers—we covered a large amount of generically useful information, especially Modules, Class Variables, and external data storage and retrieval using either XML or YAML (or both). We’ve done a bit of functional programming already in the last two chapters, but ...