hash | Daniel P. Clark

May 13, 2017 by Daniel P. Clark

Don’t Use Objects as Hash Keys in Ruby*

Hashes have been optimized for symbols and strings in Ruby which technically are objects but this article is for revealing how much of a difference this makes when using other objects as hash keys. There are some cases where this makes a big difference but many times you won’t notice much of a difference. I…

November 13, 2015 by Daniel P. Clark

Implement a Lazy Hash in Ruby

I use the term Lazy Hash in the same way you would call an Enumerator a lazy iterator. That being; the values don’t get evaluated until they are needed. In a Hash this is also utilizing memoization, where the value gets assigned the first time it’s used. E.G. @variable ||= :value Let’s say you own…

May 28, 2015 by Daniel P. Clark

Rails’ HashWithIndifferentAccess

A Ruby Hash is a very powerful collection type to use in Ruby. When working in Rails sometimes you’ll have symbols as keys or sometimes they will be strings. If you use a normal Hash these will store as different keys for the same name.


sample = Hash.new
sample[:a] = 1
sample["a"] = 2
sample
# => {:a=>1, "a"=>2}

sample = Hash.new

sample[:a] = 1

sample["a"] = 2

sample

# => {:a=>1, "a"=>2}

Rails has another version of Hash that will map…

March 26, 2015 by Daniel P. Clark

Different Collection Types in Ruby

In computer science, a collection or container is a grouping of some variable number of data items (possibly zero) that have some shared significance to the problem being solved and need to be operated upon together in some controlled fashion. – Wikipedia In Ruby the most common collection types used are known as Array and…

February 4, 2015 by Daniel P. Clark

Using Ruby Object Type Classes to Safely Build Data

When building collections of data you will find situations where the types aren’t what you planned to work with. And when I say types I’m speaking generically of arrays, hashes, strings, integers, nil, etc. Everything’s cosy when you know what your getting. For example putting 10 integers into an Array:


arr = []
10.times do |num|
  arr << num
end
arr
# => [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]

arr = []

10.times do |num|

arr << num

end

arr

# => [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]

But if you want…