Design Pattern

Rails
1

Hi,

I have a collection of arbitrary objects that have a date attribute. I
want to display these objects by month. For example

@things=Thing.all

Now I want to display in a table all the things by month - how can I
do this? the problem isn’t making a table or anything it’s just the
logic for getting the min and max range for all the dates in things
and then finding the monthes to use for the scale and etc. Please give
suggestions.

Thanks,
Elder Egg

2

To work on the day/month/date portion of a date (mysql) use
DAY(your_date) MONTH(your_date) YEAR(your_date).

For instance
@things = Thing.all(:conditions => “YEAR(created_at)=2009”)

3

Sharagoz – wrote:

To work on the day/month/date portion of a date (mysql)

Not just mySQL. This is standard SQL syntax.

use
DAY(your_date) MONTH(your_date) YEAR(your_date).

For instance
@things = Thing.all(:conditions => “YEAR(created_at)=2009”)

Best,
–Â
Marnen Laibow-Koser
http://www.marnen.org
[email protected]

4

eggie5 wrote:

Hi,

I have a collection of arbitrary objects that have a date attribute. I
want to display these objects by month. For example

@things=Thing.all

Now I want to display in a table all the things by month - how can I
do this? the problem isn’t making a table or anything it’s just the
logic for getting the min and max range for all the dates in things
and then finding the monthes to use for the scale and etc. Please give
suggestions.

Well…

@things = @things.sort_by { |a, b| a.date <=> b.date }

That’ll work to sort if the date attribute has the same name on all
objects.
From there, you can also do “select” if a.date.month == 1, etc etc etc.

5

Thanks, this is what I was looking for… not just a flat collection
sorted by date but sorted by date with sub objects ( I don’t know how
to explain better).

6

Another question related to this… I have everything grouped by
common date, but now I want to do it my month. Any ideas?

7

On Wed, Feb 3, 2010 at 3:58 AM, eggie5 [email protected] wrote:

and then finding the monthes to use for the scale and etc. Please give
suggestions.

Unlike some of the other responders, I’m going to take your “arbitray
objects” to mean that they aren’t necessarily ActiveRecord models, and
therefore SQL solutions don’t apply. Assuming that each of these Ruby
objects has a method date which returns either a Date, DateTime, or
Time object then something like

@things.group_by {|thing| thing.date.to_date.beginning_of_month }

while return a hash whose keys are the dates which have at least one
thing, and whose values are arrays of things whose dates fall within
the month.

If you know that the things all will return a Date from .date then you
can leave out the to_date in the expression.

def initialize(date)
@date = date
end
attr_reader :date
end
=> nil

things = [Date.today, 2.days.from_now, 5.days.ago].map {|d| Thing.new(d)}
=> [#<Thing:0x00000101524828 @date=Wed, 03 Feb 2010>,
#<Thing:0x000001015247f0 @date=2010-02-05 14:06:22 -0500>,
#<Thing:0x00000101524780 @date=2010-01-29 14:06:22 -0500>]

things.group_by {|t| t.date.to_date.beginning_of_month}
=> {
Mon, 01 Feb 2010=>[#<Thing:0x00000101524828 @date=Wed, 03 Feb
2010>, #<Thing:0x000001015247f0 @date=2010-02-05 14:06:22 -0500>],
Fri, 01 Jan 2010=>[#<Thing:0x00000101524780 @date=2010-01-29 14:06:22
-0500>]
}

HTH

Rick DeNatale

Blog: http://talklikeaduck.denhaven2.com/
Twitter: http://twitter.com/RickDeNatale
WWR: http://www.workingwithrails.com/person/9021-rick-denatale
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