published on 13.03.2006 00:59.

Ruby tip of the day (2)

Comparing objects in Ruby

UPDATE: the title is a bit misleading, it should better be “sorting ruby objects” or something like that. the point is to show that ruby’s collections have several methods to compare their contents - and that the comparison rule can be given in a block.

you have a couple of objects in a collection. you want to find out which of the objects has the highest position.


class SomeFoo
  attr_reader :age
  def initialize(age)
    @age = age
  end
end

list = [
  SomeFoo.new(45),
  SomeFoo.new(18),
  SomeFoo.new(29)
]

oldest_foo =  list.max {|a,b| a.age <=> b.age}
puts oldest_foo.age
=> 45

of course this comparison works for anything you can write a block for.

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published on 01.03.2006 12:58.

MySql tip of the day

using regular expressions for criteria

SELECT style_number, LENGTH(style_number) 
FROM articles 
WHERE style_number REGEXP '^(89|98)[0-9]+$'

you can also use RLIKE. and it runs much faster than expected, too!

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