Ruby supports operator overloading — operators behave as methods of an object. So, << behaves differently based on the context. Generally for anything other than bit shifting << means to append or concatenate, such as with a string or an array. Concatenate is generally faster than addition — new objects are not created.
matt:~$ irb
>> 32 << 3
=> 256
>> "cat" << 'nip'
=> "catnip"
>> [0,2] << 2
=> [0, 2, 2]
open-uri, a part of the standard Ruby distribution, makes opening and reading from a URI easy. With it, developers use familiar methods like open for performing I/O with URI’s.
require 'open-uri'
open("http://www.ruby-lang.org/") {|f|
f.each_line {|line| p line}
}
Contrast Net::HTTP which uses numerous methods to achieve the same effect.
require 'net/http'
url = URI.parse('http://www.example.com/index.html')
req = Net::HTTP::Get.new(url.path)
res = Net::HTTP.start(url.host, url.port) {|http|
http.request(req)
}
puts res.body
An addon, SuperIO, adds more flexiblity in attempting to DTRT.
Conventions are one of Ruby‘s nicest features, making it easier to read and maintain. One convention is that methods which may modify an object have a ‘!’ in their name, such as ‘chop!’, which indicates if there are no changes, then nil is returned. This can cause issues with method chaining.
Elsewhere I’ve written about mini-sagas. I’m setting a goal to write one about a ruby topic daily. It will limit me to fifty words. But there certainly can be a great deal of freedom arising through constraints. It’s been said, in fact, that Creativity loves constraints. Here’s to creative constraint!
A question was raised on comp.lang.ruby by Li Chen regarding recursion being used to convert decimals to binary. What follows is my response.
Continue reading ‘Recursion’
