math.type (x) Returns "integer" if x is an integer, "float" if it is a float, or nil if x is not a number.

lua_remove[-1, +0, –] void lua_remove (lua_State *L, int index); Removes the element at the given valid index, shifting down the elements above this index to fill the gap. This function cannot be called with a pseudo-index, because a pseudo-index is not an actual stack position.

debug.setuservalue (udata, value) Sets the given value as the Lua value associated to the given udata. udata must be a full userdata. Returns udata.

tostring (v)string.format If the metatable of v has a __tostring field, then tostring calls the corresponding value with v as argument, and uses the result of the call as its result.

3.3.6 – Function Calls as Statements To allow possible side-effects, function calls can be executed as statements: stat ::= functioncall In this case, all returned values are thrown away. Function calls are explained in §3.4.10.

string.rep (s, n [, sep])nssepsepn (Note that it is very easy to exhaust the memory of your machine with a single call to this function.)

io.tmpfile () In case of success, returns a handle for a temporary file. This file is opened in update mode and it is automatically removed when the program ends.

string.match (s, pattern [, init])matchpattern§6.4.1smatchnilpatterninit

lua_rawlen[-0, +0, –] size_t lua_rawlen (lua_State *L, int index); Returns the raw "length" of the value at the given index: for strings, this is the string length; for tables, this is the result of the length operator ('#') with no metamethods; for userdata, this is the size of the block of memory allocated for the userdata; for other values, it is 0.

dofile ([filename])dofilestdindofiledofile