Converting elements of 2d-array

Question

I have the following 3x3 array:

grid = [["1","2","3"],["4","5","6"],["7","8","9"]]

I want to convert each number from a String to a Fixnum. I tried:

grid.each{ |thing| thing.each { |subthing| subthing = subthing.to_i }}

However, puts grid[0][0].class still outputs String.

Aaron Hinni · Accepted Answer · 2013-03-21 21:04:55Z

2

each just iterates over each value, it doesn't change the contents. Try using map.

foo = grid.map{ |a| a.map(&:to_i) }  # foo => [[1,2,3,],[4,5,6],[7,8,9]], but grid is still the original

If you want to update grid in place:

grid.each { |a| a.map!(&:to_i) }

edited Mar 21, 2013 at 21:04

answered Mar 21, 2013 at 20:38

Aaron Hinni

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1 Comment

dbenhur Over a year ago

Slightly more efficient: grid.each { |a| a.map!(&:to_i) }. No need need to make new inner arrays, just replace their elements in place with Array#map!.

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