Adding together objects in a group_by array

Question

I have an array of transactions, each looks like this...

Transaction:0xc3b8de4 @id="p5qvzdyQZeTyKk97ozbAhAeN0DwVgMh6re13Z", @account="N08xNQywYVUZaqoN9bwAI6BbeBrzyAfKmpzQe", @date="2014-02-03", @amount=100, @name="COMED 4131 Reference#", @meta={"is_risky"=>false, "location"=>{"store_number"=>"10818"}}, @location=nil, @pending=false, @score={"location"=>{}, "name"=>0.2}, @type={"primary"=>"unresolved"}, @category=nil, @category_id=nil>]}

I want to group the transactions by month so I have this...

@income_by_month = @payroll_transactions.group_by { |t| t.date.to_date.month })

Which groups the transactions by month.

Now I need a sum of the "amount" object in each months transactions. So I need the total of all amount for each month. Here is what I have so far but I have not been successful.

@payroll_transactions = @user.transactions.find_all { |t| t.category_id == '21009000' } #finds all payroll transactions for all months
@income_by_month = @payroll_transactions.group_by { |t| t.date.to_date.month }) #groups transactions into month groups
@income_by_month.map(&:amount).inject(0, &:+) #I need a method to sum the total of amounts for each month

Thanks in advance

BroiSatse · Accepted Answer · 2015-04-18 22:56:55Z

1

This should do:

@income_by_month = @payroll_transactions.group_by { |t| t.date.to_date.month }).map do |month, transactions|
  [month, transactions.sum(&:amount)]
end.to_h

answered Apr 18, 2015 at 22:56

BroiSatse

44.8k8 gold badges63 silver badges89 bronze badges

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

Comments

t56k · Accepted Answer · 2015-04-18 22:54:37Z

0

What about this? compact removes nil values, don't know if you'd need that or not.

@income_by_month.map(&:amount).compact.reduce(&:+)

You might need a @income_by_month.month(:april).map... if I understand you correctly, and you may still need to implement that.

answered Apr 18, 2015 at 22:54

t56k

7,03110 gold badges59 silver badges122 bronze badges

Collectives™ on Stack Overflow

Adding together objects in a group_by array

2 Answers 2

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related