增加一个 ruby​​ 字符串插值循环

Question

I am trying to make data variable increments by 1 every time it gets collected in the barcode array.

 def generate_barcode
    batch_number = params[:batch_number].to_i
    business_partner_id = params[:business_partner].to_i
    current_business_partner = BusinessPartner.find(business_partner_id)

    serial_number = "00000000"
    final_value = current_business_partner.partner_code << serial_number

    barcodes = batch_number.times.collect {
      data = "#{final_value + '1'}" 

      Barby::EAN13.new(data) #currently collecting the same object batch number of times with data value being the same......

    }
  end

How do I increment data by 1 each time the collect happens?

Answer 1

Ruby has a handy helper method for "incrementing" strings, called succ / succ! . Observe:

serial_number = "00000000"

15.times { puts serial_number.succ! }
# >> 00000001
# >> 00000002
# >> 00000003
# >> 00000004
# >> 00000005
# >> 00000006
# >> 00000007
# >> 00000008
# >> 00000009
# >> 00000010
# >> 00000011
# >> 00000012
# >> 00000013
# >> 00000014
# >> 00000015

Answer 2

Meditate on this:

5.times { |i| i } # => 5
5.times.collect{ |i| i * 2 } # => [0, 2, 4, 6, 8]

The documentation for times shows it passes a value each time it iterates.

Iterates the given block int times, passing in values from zero to int - 1.

Answer 3

Your question isn't easy to understand because it isn't clear what you want to accomplish. From what I understood you want to increment "00000000" > "00000001", etc.

For that you could use String.rjust :

number_of_digits = 8
serial_number = 0 # Use an integer!!!

barcodes = batch_number.times.collect {
    serial_number += 1

    data = serial_number.to_s.rjust(number_of_digits, '0')

    # Do what you want with data
}

Best wishes!

Update: Sergio Tulentsev's answer is very handy too and even more elegant for this problem, but if you want more control over the serial number, this would be the way.