what is a table used for lua code example

Example 1: lua tables

local favoritefoods_table = {"hamburger", "spaghetti", "pizza", "potato chips"}
--the table--

for i, v in pairs(favoritefoods_table) do --loop through the table-- 
	print(i) --print the number--
  	print(v) --print the value--
end

Example 2: table lua

a = {}
    x = "y"
    a[x] = 10                 -- put 10 in field "y"
    print(a[x])   --> 10      -- value of field "y"
    print(a.x)    --> nil     -- value of field "x" (undefined)
    print(a.y)    --> 10      -- value of field "y"