Ruby: Sorting an array that is "linked" to another array

Question

In my rails app, I have a loop in my controller that does this:

event_prices = []
event_dates = []
for event in @customer.events
  event_prices.push(event.total_prices)
  event_dates.push(event.event_time.strftime("%b %d, %Y at %I%p"))
end

I then use the arrays to push data into a highcharts graph. What I want to do is sort the event_dates array in order, but if I do that, I'll lose the order of the event_prices. Right now, the event_price[1] corresponds to event_dates[1] and so on, but if I call a sort! on event_dates, it won't sort event_prices along with it.

So how can I get it so that I sort both arrays the same way?

Harish Shetty · Accepted Answer · 2010-08-19 07:52:46Z

4

It's better to use DB for sorting. I would do the following:

event_prices, event_dates = 
  @customer.events(:order => "event_time ASC").map do |e|
    [e.total_prices, e.event_time.strftime("%b %d, %Y at %I%p")]
  end.transpose

answered Aug 19, 2010 at 7:52

Harish Shetty

64.4k21 gold badges154 silver badges201 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

rfunduk · Accepted Answer · 2010-08-19 02:39:16Z

2

How about something like:

event_prices = []
event_dates = []
@customer.events.sort_by { |e| e.event_time }.each do |event|
  event_prices << event.total_prices
  event_dates << event.event_time.strftime("%b %d, %Y at %I%p")
end

answered Aug 19, 2010 at 2:39

rfunduk

30.5k5 gold badges61 silver badges55 bronze badges

5 Comments

Reti Over a year ago

Wow, you are a ruby wizard :) Thanks

rfunduk Over a year ago

Btw this will by default sort them oldest to newest. To get the reverse you could just reverse the list, or alternatively save off the current date now = Time.now and then make the block to sort_by like so: now - e.event_time.

Reti Over a year ago

Thanks again. I actually want oldest to newest, so this is great :)

rfunduk Over a year ago

No problem. Let me know if you have a problem... just in case I fat-fingered it. Also keep in mind that you can do this through your association (as in @customer.events(...) or using named scopes like defining @customer.ordered_events) but this might not be a big deal for your use-case. Take a look at the active record association docs.

rfunduk Over a year ago

For named scope, try starting here: railscasts.com/episodes/108-named-scope

Collectives™ on Stack Overflow

Ruby: Sorting an array that is "linked" to another array

2 Answers 2

Comments

5 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

5 Comments

Your Answer

Sign up or log in

Post as a guest

Related