search for: read_at

I'm an absolute R newbie, but my question is (or at least seems) simple: I have a number of sensor values from different sensors, along with timestamps, so something like this: sensor 1: read_at: 1 2 4 5 6 value: 1 15 8 15 23 sensor 2: read_at: 2 3 4 6 7 value: 10 11 7 12 28 what I need is a line plot of the sensor values, aligned given their timestamps (it's in unix epoc time). which data structure should i use? ca...

I am trying to create a messaging system for my users but I''m having a hard time designing my db. This is what i have in mind, but I am not sure if its the best approach. user has_one inbox user has_one outbox inbox has_many messages outbox has_many messages inbox table user_id outbox table user_id messages table box_id (refers to either inbox or outbox - how?) from_id to_id

...ion) there is an example of (within ActiveRecord) marking an article as read by a user at the present time. Short example code (from the book) here: class User < ActiveRecord::Base has_and_belongs_to_many :articles def read_article(article) articles.push_with_attributes(article, :read_at => Time.now) end # ... end However, it seems this piece of code would only work the first time you read a specific article. It appears to always create a new join table post, and not to just update if there is an existing post. How would one best solve this? -- Posted via http://w...

...ion) there is an example of (within ActiveRecord) marking an article as read by a user at the present time. Short example code (from the book) here: class User < ActiveRecord::Base has_and_belongs_to_many :articles def read_article(article) articles.push_with_attributes(article, :read_at => Time.now) end # ... end However, it seems this piece of code would only work the first time you read a specific article. It appears to always create a new join table post, and not to just update if there is an existing post. How would one best solve this? -- Posted via http://w...

...of rows in one step. Now, if two objects I want to associate already exist, how do I create the join row? The Agile book mentions the ''push_with_attributes'' method. The text says this method is useful for adding additional attributes to the join row (in the example a ''read_at'' timestamp). I only require a simple two-key join row - is ''push_with_attributes'' the way to go? -Lindsay -- Posted via http://www.ruby-forum.com/.

Heyo! I am setting up a self-referencial habtm relationship with the users of my app. I am using Chad Fowler''s "Rails Recipes" to get me started, and everything works great with the join table "people_friends". I add friends by doing somebody.friends << somebodyelse. However, with my app, there is an approval process so my join table has columns person_id,