ruby - IO.readlines to multidimensional array -

the goal of program read in file has grid of numbers delimited white space. process in program need multidimensional array. attempted by:

arr = io.readlines("example.txt")   arr.map { |string| string.chomp.split.map { |sub_str| sub_str.to_i } }   

this code, when ran, return original array, strings , '\n'. have been able desired effect by:

arr = io.readlines("example.txt")   int = array.new   arr.each { |string| int << string.chomp.split.map { |sub_str| sub_str.to_i } }   

i prefer mutate original array rather created new one. how can map array desired results? new ruby , enjoying oop'ness. help.

just reassign original array

arr = arr.map { |string| string.chomp.split.map { |sub_str| sub_str.to_i } }  

or use destructive map!

arr.map! { |string| string.chomp.split.map { |sub_str| sub_str.to_i } }