lua how to print a table code example

Example 1: print table lua

function print_table(node)
    local cache, stack, output = {},{},{}
    local depth = 1
    local output_str = "{\n"

    while true do
        local size = 0
        for k,v in pairs(node) do
            size = size + 1
        end

        local cur_index = 1
        for k,v in pairs(node) do
            if (cache[node] == nil) or (cur_index >= cache[node]) then

                if (string.find(output_str,"}",output_str:len())) then
                    output_str = output_str .. ",\n"
                elseif not (string.find(output_str,"\n",output_str:len())) then
                    output_str = output_str .. "\n"
                end

                -- This is necessary for working with HUGE tables otherwise we run out of memory using concat on huge strings
                table.insert(output,output_str)
                output_str = ""

                local key
                if (type(k) == "number" or type(k) == "boolean") then
                    key = "["..tostring(k).."]"
                else
                    key = "['"..tostring(k).."']"
                end

                if (type(v) == "number" or type(v) == "boolean") then
                    output_str = output_str .. string.rep('\t',depth) .. key .. " = "..tostring(v)
                elseif (type(v) == "table") then
                    output_str = output_str .. string.rep('\t',depth) .. key .. " = {\n"
                    table.insert(stack,node)
                    table.insert(stack,v)
                    cache[node] = cur_index+1
                    break
                else
                    output_str = output_str .. string.rep('\t',depth) .. key .. " = '"..tostring(v).."'"
                end

                if (cur_index == size) then
                    output_str = output_str .. "\n" .. string.rep('\t',depth-1) .. "}"
                else
                    output_str = output_str .. ","
                end
            else
                -- close the table
                if (cur_index == size) then
                    output_str = output_str .. "\n" .. string.rep('\t',depth-1) .. "}"
                end
            end

            cur_index = cur_index + 1
        end

        if (size == 0) then
            output_str = output_str .. "\n" .. string.rep('\t',depth-1) .. "}"
        end

        if (#stack > 0) then
            node = stack[#stack]
            stack[#stack] = nil
            depth = cache[node] == nil and depth + 1 or depth - 1
        else
            break
        end
    end

    -- This is necessary for working with HUGE tables otherwise we run out of memory using concat on huge strings
    table.insert(output,output_str)
    output_str = table.concat(output)

    print(output_str)
end

Example 2: lua print contents of table

for k,v in pairs(table) do
 print(v)  
end

Example 3: where do lua tables start

tbl = {"yes"}
tbl[1]
-- Arrays/Tables start at 1

Example 4: lua dump table

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

Example 5: lua print all elements table

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"
   }
}

for index, data in ipairs(people) do
    print(index)

    for key, value in pairs(data) do
        print('\t', key, value)
    end
end