How to implement a search function for array of classes - arrays

Question

I have a User class as follows:
class User
attr_reader :username, :password
def inintialize(username, password)
#username = username
#password = password
end
end
And I want to store many of these User classes in an array as follows:
users = []
def initialize_users
user = User.new("user0", "password0")
users.push(user)
user = User.new("user1", "password1")
users.push(user)
end
And now I want to implement a searching function where I can search via username, or password. I know I can iterate over the classes comparing each field like so:
def search(username)
users.each do |user|
if user.username == username then
puts "Found"
break
end
end
end
But is there any other way to do this without the iterating or is this simply the easiest/cleanest way?
I was thinking maybe there is a way to do something like:
users["username_to_find"]
=> true
Although I am not sure how to implement that. I would believe I would have to rewrite the User class to have a built in list, but from there I am lost. I guess even if I do implement this feature there is still a iteration that has to happen.
Also I would like to access that users data from within that notation such as
users["username_to_find"].password
=> "password111"
Anyone have any ideas?
PS: User class is reduced to relevant code, it actually holds many more data members which are specific to each user such as sockets, and methods for sending data to a specific users sockets.

Answer 1

You really have no choice but to iterate over every element of the array and perform your matching test. Enumberable#detect is what you would want to use:
def search(username)
# return the first matching result
users.detect { |user| user.username == username }
end
This would return the first User with a matching username or nil. If you want to allow multiple results to be returned (e.g. more of what the word "search" denotes) than you would want to use Enumberable#select which returns all matching blocks:
def search(username)
# return ALL matching results
users.select { |user| user.username == username }
end
If you need to potentially match on multiple criteria (e.g. search on username and first name, etc) than you will need to take this approach. If you are only searching on username, than the solution given by #dax above is perfect.

Answer 2

If it doesn't need to be an Array, why not use a Hash? It provides exactly the functionality you want.
users = {}
user = User.new("user0", "password0")
users[user.username] = user
Access it like so
users['tim_the_toolman'] # => nil, there is no user by that name
users['user0'] # => returns user0
users['user0'].password # => 'password0'

Answer 3

use Array find and select methods. Assume you are searching by name
find returns first object which satisfies your condition
array.find { |user| user.name == searched_name } # will be either one User or nil, if neither has name eq to searched_name
select returns all objects which satisfy your condition
array.select { |user| user.name == searched_name } #will be either array of Users which have name eq searched_name or an empty array when none has this name