Basic lua: Tables

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Revision as of 21:15, 2 September 2022 by AFRLme (talk | contribs)

Tables are one of the features of Lua script, that make the scripting language so dynamic & easy to use, as they allow us to easily create tables, insert, remove & sort data. Tables are often comprised of arrays that usually involve keywords - or an index number - & a value. Tables can be accessed using multiple different methods.

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Creating a table

method 1: automatically generated index values
local t = {1, 2, 3, 4, 5, "six", 7, "ate", 9} -- automatically assigns an index number to each value starting from 1
local str = "" -- empty string

for i = 1, #t do -- for 1 to table total, print value of index number
 str = str .. t[i] -- add current table index value to existing text data in the str variable
 if i < #t then str = str .. ", " end -- if i is less than table entry total then insert ", " into the str variable
end

print("table data: " .. str) -- print the table data
print( "table entry total: " .. #(t) ) -- print total of table entries
Basic lua (tables) 1.png
method 2: manually created index values
local t = {

[1] = 1,
[2] = "two",
[3] = 3,
[4] = 2 * 2,
[5] = "five",

}

local str = "" -- empty string

for i = 1, #t do -- for 1 to table total, print value of index number
 str = str .. t[i] -- add current table index value to existing text data in the str variable
 if i < #t then str = str .. ", " end -- if i is less than table entry total then insert ", " into the str variable
end

print("table data: " .. str) -- print the table data
print( "table entry total: " .. #(t) ) -- print total of table entries
Basic lua (tables) 2.png
method 3: keywords & values
local t = {

["hello world"] = "hello world",
example = "this also works",
camelCaseExample = "this will also work",
snake_case_example = "as will this"

}

for k, v in pairs(t) do
  print(k ..": " .. v)
end

print("\n...but as you can see it does not necessarily return them in the order they were created")
Basic lua (tables) 3.png
method 4: auto generated index entries with sub-arrays containing keywords
local t = {

{x = 100, y = 300},
{x = 200, y = 111}

}

print("x = " .. t[1].x .. ", y = " .. t[1].y)
Basic lua (tables) 4.png


method 5: keyword tables with keyword sub-arrays containing keywords
local t_texts = {

["English"] = {
    {txt = "hello world!"},
    {txt = "goodbye world!"}
},

["German"] = {
  {txt = "hallo welt!"},
  {txt = "auf wiedersehen welt"}
}

}

print( t_texts["English"][1].txt )
Basic lua (tables) 5.png
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