ruby - Search for zero in 2D array and make a corresponding row and col 0 -

this code, works, it's big. want refactor it.

req_row = -1 req_col = -1  a.each_with_index |row, index|   row.each_with_index |col, i|      if col == 0         req_row = index         req_col =         break      end   end end  if req_col > -1 , req_row > -1   a.each_with_index |row,index|     row.each_with_index |col, i|       print (req_row == index or == req_col) ? 0 : col        print " "     end     puts "\r"   end end 

input: 2d array

1  2  3  4  5  6  7  8 9  10 0 11 12 13 14 15   

required output:

1  2  0  4  5  6  0  8 0  0  0  0 12 13 0  15   

i'm surprised matrix class not used more:

a = [[ 1,  2,  3,  4],      [ 5,  6,  7,  8],      [ 9, 10,  0, 11],      [12, 13, 14, 15]]  require 'matrix'  m = matrix.rows(a)   #=> matrix[[1, 2, 3, 4], [5, 6, 7, 8], [9, 10, 0, 11], [12, 13, 14, 15]]  r, c = m.index(0)   #=> [2, 2]  matrix.build(m.row_count, m.column_count) {|i,j| (i==r || j==c) ? 0 : m[i,j]}.to_a   #=> [[ 1,  2, 0,  4],   #    [ 5,  6, 0,  8],   #    [ 0,  0, 0,  0],   #    [12, 13, 0, 15]]  

note matrix objects immutable. change individual elements must create new matrix.

a slight modification required if wish every 0 in matrix:

a = [[ 1,  2,  3,  4],      [ 5,  6,  7,  8],      [ 9, 10,  0, 11],      [ 0, 13, 14, 15]]  require 'set'  m = matrix.rows(a)   #=> matrix[[1, 2, 3, 4], [5, 6, 7, 8], [9, 10, 0, 11], [0, 13, 14, 15]]  zero_rows = set.new zero_columns = set.new m.each_with_index { |e,i,j| (zero_rows << i; zero_columns << j) if e.zero? } zero_rows   #=> #<set: {2, 3}>  zero_columns   #=> #<set: {2, 0}>       matrix.build(m.row_count, m.column_count) |i,j|   (zero_rows.include?(i) || zero_columns.include?(j)) ? 0 : m[i,j] end.to_a   #=> [[0, 2, 0, 4],   #    [0, 6, 0, 8],   #    [0, 0, 0, 0],   #    [0, 0, 0, 0]]