Wednesday, May 1, 2013

Ruby Idioms part 1

Ruby is like a language in that it has phrases that are used, and ones that work better than others. The most common rubyism is a ||= b where a is set to b if it is not nil, false or undefined. It basically means if has a value move on but if it doesn't set it to b. Simple enough.

But an even more powerful one but less well known is the index feature one. Arrays, hashes and even more importantly strings have this function too.

In hashes it's the normal way to get a value by sending it its key. So:
hashy = {:key1 =>  :value1, :key2 => {:subkey1 => :subvalue1}}
doing
hashy[:key1]
will spit out
:value1 
But it's really useful for strings too.

stringy = "Friends, Romans, countrymen, lend me your ears;"
stringy['lend me your ears'] #=> "lend me your ears"

You can also chain this calls which leads to some weird things.

stringy['lend me your ears'].upcase['EARS']   #=>  "EARS"

I just used a bit of this actual code on a real project where an if statement was failing an equality check so I would've been forced to use a heavy regex to check wether the language string was 'en' or 'es'. Here is the code:


  englang = (@lang['en']) ? 'active' : ''
  spalang = (@lang['es']) ? 'active' : ''


This code was part of a haml partial that changed the class of the item to active depending on the language. Here is the haml:

  %button#english{:type => "button", :class => "btn btn-mini btn-inverse #{englang}"}English

No comments:

Post a Comment