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Ruby Ruby Objects and Classes Build a Bank Account Class Printing The BankAccount

Posted by Kevin Miner
Kevin Miner
Courses Plus Student 2,831 Points

Ruby Objects and Classes extra credit: using the inject method.

The objective of the extra credit is to use the inject method to calculate the balance of the bank_account instance of the BankAccount class. I am a little fuzzy on how inject works but I feel worse about not knowing how to pass/specify the hash values of the transaction array into the injection method.

The original balance method works and has been commented out in favor of the ill-fated attempt at a balance method that calculates the balance using inject.

Would appreciate someone taking a look! Thanks in advance!

bank_account.rb 
class BankAccount
  attr_reader :name

  def initialize(name)
    @name = name
    @transactions = []
    add_transaction("Beginning Balance", 0)
  end

  def balance
    balance = 0
    @transactions.each do |transaction|
      balance += transaction[:amount]
    end
    balance
  end

  def debit(description, amount)
    add_transaction(description, -amount)
  end

  def credit(description, amount)
    add_transaction(description, amount)
  end

  def add_transaction(description, amount)
    @transactions.push(description: description, amount: amount)
  end

end

1 Answer

Avram Stern
Avram Stern
12,604 Points
Avram Stern
Avram Stern
12,604 Points

Hey Kevin Miner give this a try

def balance
     @transactions.inject(0.0) { |balance, transaction| balance + transaction[:amount] }
end

The inject method is kind of difficult to understand, but basically what it does is that it takes a collection and reduce it to a single value. Going over the ruby documentantion of the inject method might confuse you as it did with me. So just look for examples and go from there.

Hope this works!