This article is quite old.Time flies when you're having fun. I've been writing for my blog for a long time. Stuff changes fast, especially in the Ruby world. That's why I've put this warning on old posts. The article might still be valid, though.
Rails 3 is coming. All the big changes are spoken of elsewhere, so I'm going to mention some small changes. Here are 3 random new methods added to ActiveSupport:
First up is
Object#presence which is a shortcut for
Object#present? && Object. It is a bit of a sanitizer. Empty strings and other blank values will return
nil and any other value will return itself. Use this one and your code might be a tad cleaner.
"".presence # => nil "foo".presence #=> "foo" # without presence: if params[:foo].present? && (foo = params[:foo]) # .. end # with presence: if foo = params[:foo].presence # ... end # The example Rails gives: state = params[:state] if params[:state].present? country = params[:country] if params[:country].present? region = state || country || 'US' # ...becomes: region = params[:state].presence || params[:country].presence || 'US'
I like this way of cleaning up you're code. I guess it's Rubyesque to feel the need to tidy and shorten your code like this.
Another funny one is
Array.uniq_by (and it sister-with-a-bang-method). It works as select, but returns only the first element from the array that complies with the block you gave it. Here are some examples to illustrate that:
[ 1, 2, 3, 4 ].uniq_by(&:odd?) # => [ 1, 2 ] posts = %W"foo bar foo".map.with_index do |title, i| Post.create(:title => title, :index => i) end posts.uniq_by(&:title) # => [ Post("foo", 0), Post("bar", 1) ] ( and not Post("foo", 2) ) some_array.uniq_by(&:object_id) # same as some_array.uniq
And the final one for today is
exclude? which is the opposite of
include?. Nobody likes the exclamation mark before predicate methods.
# yuck: !some_array.include?(some_value) # better: some_array.exclude?(some_value)
And it also works on strings:
# even more yuck: !"The quick fox".include?("quick") # => false # better: "The quick fox".exclude?("quick") # => false
The full release notes of Rails 3 can be read here.