Ruby - Generate array of comma separated arrays - ruby-on-rails

Question

I'm trying to create a Google chart using GoogleVisualr.
This input works:
data_table.add_rows([
['04/14', 1],
['04/15', 2],
['04/16', 3],
['04/17', 4],
['04/18', 5],
['04/19', 1],
['04/20', 12],
['04/21', 13],
['04/24', 14],
['04/14', 15],
['04/24', 16],
['04/22', 17],
['04/14', 18],
['04/4', 19],
])
I am currently using:
Product.find(:all, :order => "created_at ASC").each do |p|
data_table.add_rows([
[p.created_at.strftime("%m/%d"), p.rating]
])
which returns:
01/13
2
01/20
3
02/22
2
03/14
2
03/19
2
04/14
1
04/15
2
04/17
2
05/14
2
05/14
2
05/14
2
05/14
2...
How can I format my array to match what GoogleVisualr requires:
[ [data, value], [date, value]...]

Answer 1

No need to use a loop, just use map:
rows = Product.all.order("created_at ASC").map do |p|
[p.created_at.strftime("%m/%d"), p.rating]
end
data_table.add_rows(rows)

Answer 2

This code "Product.find(:all, :order => "created_at ASC")" you can create a :scope and your controller assigns #products = Product.order_by_created
#products.inject([]) do {|result, p| result << [p.created_at.strftime("%m/%d"), p.rating])}

Answer 3

Since you're already looping over each row, you can just use DataTable#add_row.
Product.find(:all, :order => "created_at ASC").each do |p|
data_table.add_row([p.created_at.strftime("%m/%d"), p.rating])
end

Answer 4

Make it into a string and interpolate your values within it.
puts "data_table.add_rows(["
Product.find(:all, :order => "created_at ASC").each do |p|
puts "['#{p.created_at.strftime("%m/%d")}', #{p.rating}],"
end
puts " ])"

Answer 5

Try something like this
pry(main)> result = []
=> []
pry(main)> Project.find(:all, :order => "created_at ASC").each do |p|
pry(main)* result << [p.created_at.strftime("%m/%d"), p.id]
pry(main)* end
pry(main)> result
=> [["02/05", 1],
["02/14", 6],
["02/15", 7],
["02/18", 8]]

Answer 6

Probably not the most efficient way, but premature optimisation is the root of all evil:
#products = Product.all(:order => 'created_at ASC')
#csv = CSV.generate do |csv|
csv << ["Secret", "Timestamp"]
#products.each { |secret|
csv << ["#{secret.story}", "#{secret.updated_at.strftime('%s')}"]
}
end
#csv

Answer 7

If you look at the Google Visualr API (https://github.com/winston/google_visualr) on Winston's Github page, you will see that the add_rows method requires a nested array, where each element of the array is another array of size (length) 2. The first element e[0] is the date and the second element e[1] is the data value for that date. Pass your data in this format, and it should work correctly.
It looks like your code should already be doing that, as far as we can tell from here without actually being on your machine. However, your code is calling the add_rows method for each iteration in your each method, and supplying the data_table.add_rows method with a nested array that only has one array inside of it.
So instead of looking like this:
[ ['04/14', 1],
['04/15', 2],
['04/16', 3],
['04/17', 4] ]
and calling add_rows just one time like you would normally do, you are calling add_rows over and over again like this:
add_rows ( [ ['04/14', 1] ] )
add_rows ( [ ['04/15', 2] ] )
add_rows ( [ ['04/16', 3] ] )
add_rows ( [ ['04/17', 4] ] )
once for each data point.
What you should do is use your each iterator to put each date and its corresponding data value into an array, then call add_rows with that array as the parameter. Something like this:
my_array = []
Product.find(:all, :order => "created_at ASC").each do |p|
my_array << [p.created_at.strftime("%m/%d"), p.rating]
end
data_table.add_rows(my_array)
I hope this helps.