How to generate symbols inside a loop in ruby - ruby-on-rails

Question

I have a section of a web app that passes a hash of values like this for each of the order_items in an order.
Like this:
def example_method
values = {
amount_1: order_items.first.unit_price,
item_name_1: order_items.first.unit_price,
quantity_1: order_items.first.quantity,
amount_2 order_items.second.unit_price,
item_name_2: order_items.second.unit_price,
quantity_2: order_items.second.quantity,
}
end
I'm trying to generate a solution where I have a variable like n = 1 and generate the symbols for each order_item using n like this:
def example_method
values = {
n=1
order_items.each do |item|
:"amount_#{n}" => item.unit_price,
:"item_name_#{n}" => item.name,
:"item_number_#{n}" => item.id,
:"quantity_#{n}" => item.quantity,
n += 1
end
end
I tried this syntax outside of the loop and it works perfectly to generate the symbols using the variable, the problem is that I get a Syntax Error when the code is inside the loop:
How can I achieve this behavior inside my code?
What am I missing?
#edit
Edit for a proposed solution:
values = {
# The rest of static values on the hash...
}
n = 1
items = order_items.each do |item|
{
"amount_#{n}".to_sym => item.unit_price,
"item_name_#{n}".to_sym => item.printer.name,
"item_number_#{n}".to_sym => item.id,
"quantity_#{n}".to_sym => item.quantity,
}
n += 1
end
values.merge(items)

Answer 1

please try this
n=1
order_items.each do |item|
"amount_#{n}".to_sym => item.unit_price,
"item_name_#{n}".to_sym => item.name,
"item_number_#{n}".to_sym => item.id,
"quantity_#{n}".to_sym => item.quantity,
n += 1
end
#edit
items = order_items.each do |item|
"amount_#{n}".to_sym => item.unit_price,
"item_name_#{n}".to_sym => item.name,
"item_number_#{n}".to_sym => item.id,
"quantity_#{n}".to_sym => item.quantity,
n += 1
end
old_hash.merge(items)
maybe you could running this and merge with outside hash
edit 2
you can install gem 'pry' to a better debug solution. For more info check this videos RailsCast Pry Debug
values = {
# The rest of static values on the hash...
}
n = 1
items = order_items.each do |item|
{
"amount_#{n}".to_sym => item.unit_price,
"item_name_#{n}".to_sym => item.printer.name,
"item_number_#{n}".to_sym => item.id,
"quantity_#{n}".to_sym => item.quantity,
}
n += 1
end
binding.pry # this will able a ruby shell prompt and you can execute your code and analyse the values
values.class # in pry prompt
items.class # in pry prompt
values.merge(items)
#edit 3
#items = {}
order_items.each do |item|
#items = {
"amount_#{n}".to_sym => item.unit_price,
"item_name_#{n}".to_sym => item.printer.name,
"item_number_#{n}".to_sym => item.id,
"quantity_#{n}".to_sym => item.quantity}
values = values.merge(#items)
n += 1
end

Answer 2

You can't use the new symbol syntax with interpolation, it has to be the old one. Also, mutating an index inside the loop is a bad practice in general in Ruby, use each_with_index instead:
order_items.each_with_index do |item, index|
{
:"amount_#{index}" => item.unit_price,
:"item_name_#{index}" => item.name,
:"item_number_#{index}" => item.id,
:"quantity_#{index}" => item.quantity,
}
end

Answer 3

Syntax as such
amount_1: 1
is not valid as a key value needs to be wrapped in {} to be a hash or when passed as arguments to a method call.
Also since you're interpolating a string you can do the following
:"amount_#{n}" => 1
If what you're aiming to do is return an array of hashes then you want to do the following
n=0
order_items.map do |item|
n += 1
{
:"amount_#{n}" => item.unit_price,
:"item_name_#{n}" => item.name,
:"item_number_#{n}" => item.id,
:"quantity_#{n}" => item.quantity,
}
end