RoR, Can't iterate from DateTime/TimeWithZone

Question

I have a simple task where I want to take a starting date and an ending date and loop over the days/dates. This code is being used in my db:seed rake task. Currently, my code has gone through the following attempts.

(someModel.start_date.to_datetime..someModel.end_date.to_datetime).each { 
    |x| puts x 
}
 ......
(someModel.start_date...someModel.end_date).each { |x| puts x }

In each case, I get an error like this.

can't iterate from ActiveSupport::TimeWithZone
or 
can't iterate from DateTime

If anyone has any clue on how to iterate over a range of DateTimes I'd be greatly appreciative.

score 32 · Accepted Answer · answered Feb 13 '14 at 04:30

32

start = someModel.start_date.to_datetime
finish = someModel.end_date.to_datetime
while(start < finish) do
  #bunch of awesome stuff
  start += 1.day
end

answered Feb 13 '14 at 04:30

Chris Barretto

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1

Thanks for the answer Chris. I had to struggle a little bit then I read that Dates are immutable and I was on my way. – Black Dynamite Feb 14 '14 at 14:30
You got it dude. Best of luck. – Chris Barretto Feb 14 '14 at 16:23

collimarco · Answer 2 · 2016-09-30T11:04:56.540

10

You must make sure that you are dealing with a Date object (by calling to_date), then everything works as expected:

start_date.to_date.upto(end_date.to_date) {|date| puts date }

Or with a range:

(start_date.to_date..end_date.to_date).to_a

edited Sep 30 '16 at 11:04

answered Sep 30 '16 at 09:51

collimarco

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score 4 · Answer 3 · answered Feb 13 '14 at 04:05

4

You can't iterate from DateTime. But you can iterate when start and end of interval are instances of Date. Convert them if possible.

And then look at these Date methods:

to use instead of each

answered Feb 13 '14 at 04:05

vrybas

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elixir · Answer 4 · 2014-02-13T04:18:29.870

0

If you want to iterate on the range you might consider a loop and step each day using something like someModel.start_date + 1.day.to_i

edited Feb 13 '14 at 04:18

answered Feb 13 '14 at 04:13

elixir

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score 0 · Answer 5 · answered Sep 24 '21 at 19:12

Here's what we're doing to iterate by minutes over two TimeWithZones:

  # allow iteration over a set of TimeWithZones
  def self.time_map(range, step: 30.minutes, &block)
    result = []
    time = range.first
    max = range.last
    test = range.exclude_end? ? ->(t) { t < max } : ->(t) { t <= max }
    value = block_given? ? ->(t) { yield(t) } : ->(t) { t }
    while test.call(time) do
      result << value.call(time)
      time += step
    end
    result
  end

RoR, Can't iterate from DateTime/TimeWithZone

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