In showing a long lists, sometimes one would prefer to see the value arranged aligned in columns. Some examples include listing methods of an object or debugger commands. An Example: require "columnize" print columnize((1..100).to_a.map{|x| "%2d" % x}, 60) 1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 2 9 16 23 30 37 44 51 58 65 72 79 86 93 100 3 10 17 24 31 38 45 52 59 66 73 80 87 94 4 11 18 25 32 39 46 53 60 67 74 81 88 95 5 12 19 26 33 40 47 54 61 68 75 82 89 96 6 13 20 27 34 41 48 55 62 69 76 83 90 97 7 14 21 28 35 42 49 56 63 70 77 84 91 98