How to dump a table to console?

If the requirement is "quick and dirty"

I've found this one useful. Because if the recursion it can print nested tables too. It doesn't give the prettiest formatting in the output but for such a simple function it's hard to beat for debugging.

function dump(o)
   if type(o) == 'table' then
      local s = '{ '
      for k,v in pairs(o) do
         if type(k) ~= 'number' then k = '"'..k..'"' end
         s = s .. '['..k..'] = ' .. dump(v) .. ','
      end
      return s .. '} '
   else
      return tostring(o)
   end
end

e.g.

local people = {
   {
      name = "Fred",
      address = "16 Long Street",
      phone = "123456"
   },

   {
      name = "Wilma",
      address = "16 Long Street",
      phone = "123456"
   },

   {
      name = "Barney",
      address = "17 Long Street",
      phone = "123457"
   }

}

print("People:", dump(people))

Produces the following output:

People: { [1] = { ["address"] = 16 Long Street,["phone"] = 123456,["name"] = Fred,} ,[2] = { ["address"] = 16 Long Street,["phone"] = 123456,["name"] = Wilma,} ,[3] = { ["address"] = 17 Long Street,["phone"] = 123457,["name"] = Barney,} ,}

I know this question has already been marked as answered, but let me plug my own library here. It's called inspect.lua, and you can find it here:

https://github.com/kikito/inspect.lua

It's just a single file that you can require from any other file. It returns a function that transforms any Lua value into a human-readable string:

local inspect = require('inspect')

print(inspect({1,2,3})) -- {1, 2, 3}
print(inspect({a=1,b=2})
-- {
--   a = 1
--   b = 2
-- }

It indents subtables properly, and handles "recursive tables" (tables that contain references to themselves) correctly, so it doesn't get into infinite loops. It sorts values in a sensible way. It also prints metatable information.

Regards!