Hash[key] in Ruby returns nil but hash has no nil values-CodePudding

I'm working in filling a database with a .csv file in which each row is a long code. I have a hash with the positions for each column and with that I'm creating another hash that stores the column name as the key and the value. In addition I want to create some other columns based on the ones from de csv but when trying to call de values to perform operations they return nil. However, when I call the hash it shows that none of the values are nil.

Here is a sample of the .csv: file

Here is my code:

require 'rake'
require 'csv'

namespace :import do

  desc "delete old data and load data from file"
  task  rolcobro: :environment do
    SiiPropiedad.delete_all
    filename = ENV["FILE"].present? ? ENV["FILE"] : "sample.txt"
    
    rowshash = {codigo_comuna: [0,4],
      anio: [5,8],
      semestre: [9,9],
      aseo: [10,10],
      direccion: [17,56],
      manzana: [57,61],
      predio: [62,66],
      serie: [67,67],
      cuota_trimestral: [68,80],
      avaluo_total: [81,95],
      avaluo_exento: [96,110],
      anio_fin_exencion: [111,114],
      ubicacion: [115,115],
      destino: [116,117]
    }

    dir = "db/csv/"
    filepath = File.join Rails.root, "#{dir}#{filename}"

    CSV.foreach(filepath, headers: false) do |row|
            texto = row[0].to_s
            attributes = {"texto": texto}
            rowshash.each do |key,value|
                attributes[key] = texto[value[0]..value[1]]
            end
      
      #HERE THE "rol" MUST BE CREATED FROM "manzana" AND "predio". EX: IF attributes["manzana"] = "00308" AND attributes["predio"] = "00061" (AS STR) THEN attributes["rol"] should be "308-61"
            attributes["rol"] = "#{attributes["manzana"].to_i}-#{attributes["predio"].to_i}"

      #HERE IF IT IS " " I WANT THE FIRST MSG, ELSE (WHEN IT IS "A") THE LATER
            attributes["aseo"] == " " ? "Cuota trimestral no incluye aseo" : "Cuota trimestral incluye aseo"
            SiiPropiedad.find_or_create_by(attributes)
        end
  end
end

In all cases I get nothing for "rol" and for "aseo" the condition won't work. I'm sure I'm missing some basics. Can you help me please?

CodePudding user response：

Your hash keys are symbols, but you're using strings to add new keys and for lookup. For example, attributes["rol"] = "value" will make a string key "rol".

rowshash = {
  symbol:            "this is a symbol",
  "also symbol":     "symbol again",
  :"third symbol" => "another symbol",
  "string"        => "a string key"
}

rowshash[:symbol]         # => "this is a symbol"
rowshash[:"also symbol"]  # => "symbol again"
rowshash[:"third symbol"] # => "another symbol"
rowshash["string"]        # => "a string key"

You can't lookup symbol keys with strings and vice versa. When you ask for a key that doesn't exist you get the default value which is nil:

rowshash["symbol"]        # => nil
rowshash["also symbol"]   # => nil
rowshash["third symbol"]  # => nil
rowshash[:"string"]       # => nil

If you want to get a different default value, you can use default= method on the hash itself.

rowshash.default = "new default"
rowshash["not found"]     # => "new default"

https://rubyapi.org/3.1/o/hash