如何在Ruby中使用哈希

Question

I'm trying to use a hash to store the users. I have this code, and it's working, but it's not the way I want it:

@user_hash = Hash.new
@user_hash = User.all(:all)

user = Hash.new
user = @user_hash.select { |item| item["user_id"] == '001' }

puts user[0].name

How can I use something like user.name insted user[0].name ?

Answer 1

First of all, you don't need to initialise your Hashes before you use them - both calls to Hash.new are unnecessary here.

Second, your only problem is that you're using the select method. Quoting from the documentation :

Returns a new hash consisting of entries for which the block returns true.

That's not what you want. You want to use detect : Passes each entry in enum to block. Returns the first for which block is not false.

user = @user_hash.detect { |item| item["user_id"] == '001' } user = @user_hash.detect { |item| item["user_id"] == '001' } should work

Answer 2

To create a hash you should use the following syntax:

@user_hash = Hash[User.find(:all).collect{|u| [u.user_id, u]}]

Then you can do something like:

puts user["001"].name

Answer 3

user = Hash.new is a waste of time as you are overwriting it with the result of the following select .

and select returns an array of hashes that pass your test.

You want .find or its synonym .detect instead of .select .