From: Morton Goldberg <m_goldberg@...>
Date: 2006-09-12T13:59:11+09:00
Subject: Re: find_all help

On Sep 12, 2006, at 12:20 AM, kovax wrote:

> Hello,
>
> I have an array filled with employee objects that are defined like
> this:
>
> Employee = Struct.new(:name, :age)
>
> I would like to use the find_all method on an array of employee  
> objects
> to find all employee objects with an age > 18. I tried the following
> code but I was unsuccessful:
>
> employees = []
> employees.add Employee.new("joe" , 4)
> employees.add Employee.new("sam" , 20)
>
> employees.select { Employee.age > 18 }
>
> Any help or pushes in the right direction would be really appreciated.

I was tempted to answer that your code is illegal because employing  
four-year olds is illegal :), but the real answer is Array doesn't  
support 'add'. In Ruby you use 'push' or '<<'. Further, the form for  
using 'select' is:

    a_collection.select { |identifier| <code referring to identifier> }

where 'identifier' gets bound successively to elements of  
'a_collection'. So try something like:

<code>
#! /usr/bin/ruby -w

Employee = Struct.new(:name, :age)

employees = []
employees << Employee.new("joe" , 4)
employees << Employee.new("sam" , 20)

p employees.select {|e| e.age > 18 }
</code>

<result>
[#<struct Employee name="sam", age=20>]
</result>

Regards, Morton