API select

Used to traverse a list. This function is usually used to capture the arguments passed to an ellipsis (...). The official usage of this function is to return a list (retN) starting from index to the end of the list (list). local ret1, ret2, retN = select(index, list)

• index:Any non-zero number or the string "#".
• list:Usually an ellipsis (...).

• retN:The number of items in the list or every value starting from index to the end of the list.

-- Common usage. local num = select('#', ...) -- Returns the number of arguments in the ellipsis. local arg = select(i, ...) -- Returns the value at index i.

-- Print all of the function's arguments (those passed to the ellipsis (...) only) to the default chat frame. local msg for i = 1, select('#', ...) do msg = select(i, ...) DEFAULT_CHAT_FRAME:AddMessage(msg) end

local a, b, c = select(2, 'a', 'b', 'c') -- a = 'b' -- b = 'c' -- c = nil

select can be used to catenate a vararg list into an array. This is useful for returning info from GetBinding, which returns a vararg list of unknown size.

function MyAddon_Catenate(...) local t,v t = {} for i = 1, select("#", ...) do v = select(i, ...) tinsert(t, v) end return t end

-- these are identical -- number 1 local msg, r, g, b, a, id = select(1, ...) DEFAULT_CHAT_FRAME:AddMessage(msg, r, g, b, a, id)

• An alternative solution is to use a declaration like this: local args = {...} This has the advantage of being portable to standard Lua (although redundant, since standard Lua would make this assignment implicitly) and more readable to non-WoW Lua programmers.
• list can be value1, value2, value3, ... valueN; although, you will never see it used in that manner since you can just access value1 through valueN directly.
• It is not recommended that you use this method on a table as you would have to pass the table to unpack for every call to select (once plus the number of consecutive numeric indexes). For tables, use pairs or ipairs.
• Indexes beyond the number of list items will return nil.
• select(6, 'see', 'dog', 'run') -- returns nil
• An index of 0 will produce an "index out or range" error.
• Negative values wrap to the end of the list.
• select(-1, 1, 2, 3, 4, 5) -- returns 5
• A decimal index will be rounded to the nearest integer (1.1 rounds to 1, 1.9 rounds to 2).
• Passing a function that returns a list as a parameter to another function will pass each return as a parameter to the function as if you were manually passing each variable to that function, so tinsert(tab, select(1, ...)), will have unpredictable results.

-- number 2 DEFAULT_CHAT_FRAME:AddMessage(select(1, ...))