Ruby 2.6
I have an variable (integer):
num_rows = 7
I would like to turn it into an array of row numbers. I did:
rows_arr = []
num_rows = 5
i = 0
while i < num_rows
rows_arr << "Row: #{i+1}"
i += 1
end
which gives me:
=> ["Row: 1", "Row: 2", "Row: 3", "Row: 4", "Row: 5"]
Is there a cleaner, or more elegant, way of doing this?
You can do something like that:
num_rows=5
(1..num_rows).map { |n| "Row: #{n}" }
=> ["Row: 1", "Row: 2", "Row: 3", "Row: 4", "Row: 5"]
nbr_rows = 5
["Row: "].product((1..nbr_rows).to_a).map(&:join)
#["Row: 1", "Row: 2", "Row: 3", "Row: 4", "Row: 5"]
The steps are as follows.
a = (1..nbr_rows).to_a
#=> [1, 2, 3, 4, 5]
b = ["Row: "].product(a)
#=> [["Row: ", 1], ["Row: ", 2], ["Row: ", 3], ["Row: ", 4], ["Row: ", 5]]
b.map(&:join)
#=> ["Row: 1", "Row: 2", "Row: 3", "Row: 4", "Row: 5"]
See Array#product and Array#join. Note that join converts the elements of a (integers) to strings.
This is just a different way to do it, using the oft-overlooked method Array#product. In practice I prefer @Constantin's solution, as I think it reads better.
rows_arr = num_rows.times.map { |i| "Row: #{i + 1}" }
