Question

I am trying to do some math on a section of an array. And then I want to increment to do math on more of it. However I don’t know how to do it correctly.

The below code simply puts 3 columns of csv data into 1 array each. And then does math on it.

require 'csv'

csv_data = 'data.csv'

Location = []
  CSV.foreach(csv_data,'r') {|row| Location << row[0]}
Data1 = []
  CSV.foreach(csv_data,'r') {|row| Data1 << row[1]}
Data2 = []
  CSV.foreach(csv_data,'r') {|row| Data2 << row[2]}


index = 500
indexmax = 510


while index < indexmax
MathResults = Data1[index].to_f - Data2[index-1].to_f
index += 1
puts MathResults
end

If I put the MathResults above the while loop I obviously get the same result 10 times. If I put it in the loop I get 10 different results like I want but lots of errors with it that say:
warning: already initialized constant MathResults

I know this is still usable but the errors must be telling me I should be doing things differently.

So I was wondering if someone could tell me.

Thank you!

Edit: To add one thing. I realize I have 3 arrays and only 2 in use. The Location array is to later fill out the index variable after searching for the correct location. Instead of it saying just 500. Don’t worry about that.

Answer 1

You should probably use plain variable instead of constant (math_results instead of MathResults).