How to Find the Average of 3 Date in Ruby on Rails or Ruby

Find average date from collection of dates (Ruby)

Date is a bit hard to work with, you should use Time. Try converting the Dates into Times:

require 'time'
foo_time = Time.parse(foo.to_s)
bar_time = Time.parse(bar.to_s)

Convert them to timestamps, then calculate the average, then convert back to Time:

avg = Time.at((foo_time.to_f + bar_time.to_f) / 2)

You can convert that back to Date:

avg_date = Date.parse(avg.to_s)

Calculate average number of days between datetimes in Ruby

I think you have an off-by-one problem. If you have n values in dates then you'll have n-1 differences between consecutive pairs so your avg should be:

avg = difference.inject{ |sum, el| sum + el }.to_f / (arr.size - 1)

And your inject is just a long winded way of saying inject(:+) so you could say:

avg = difference.inject(:+).to_f / (arr.size - 1)

In any case, you could use map and each_cons to make it a bit nicer:

dates.map(&:to_date).each_cons(2).map { |d1, d2| d1 - d2 }.inject(:+) / (dates.length - 1)

First we can convert everything to dates in one pass with map(&:to_date) rather than converting every time we need a date instead of a string. Then the each_cons(2) iterates over the array in consecutive pairs (i.e. [1,2,3,4] is iterated as [[1,2], [2,3], [3,4]]). Then a simple map to get the differences between the pairs and inject(:+) to add them all up.

The above will leave you with a Rational but you can to_f or to_i that if you need a floating point or integer value.

Calculating the average days between records in Rails

The maximum and minimum class methods of your model will use the SQL aggregate functions min() and max() to find the extreme values efficiently.

span_secs = Foo.maximum(:created_at) - Foo.minimum(:created_at)
avg_secs = span_secs / (Foo.count - 1)
avg_days = avg_secs / (24 * 60 * 60)

Rails calculate and display average

Together with other calculations, ActiveRecord provides a method called average. You can use it by implementing something like this:

class Movie
  def self.average_by_genre(genre)
    average(:rating).where(:genre => genre)
  end
end

Alternatively, you can also implement it as an instance method of the Movie model.

class Movie
  def average_rating
    self.class.average(:rating).where(:genre => self.genre)
  end
end

This would let you call the method directly from your view.

<article>
  <header>
    <h1><%= @movie.title %></h1>
  </header>
  <p>
    <span>Average rating for genre <%= @movie.genre %>:</span> 
    <%= @movie.average_rating  %>
  </p>
</article>

ruby on rails average per day

Try using

Date.today.at_beginning_of_month.to_s(:db)

and

Date.today.tomorrow.to_s(:db)

instead.

Calculate average of column value in Ruby on Rails

You should consider reading some documentation - obviously it's quick to get a answer on SO but sometimes the docs can lead you to something you didn't know to look for or ask for.

That said, the fastest way is to use average

profile.courses.average(:gpa)

This will give you an average. Or you can do it the long way, if for some reason you need make modifications in between.

profile.courses.sum(:gpa) / profile.courses.count

Average of group by date records in Elasticsearch

I got the average by following

        average_properties_by_date:{
          avg_bucket: {
            buckets_path: 'group_by_date>_count',
            gap_policy: "skip",
            format: "#,##0.00;(#,##0.00)"
          }
        }

Be careful here _count will be used instead of doc_count.

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