pairs
Lua function

pairs

Summary

Traverse all items in a table

Prototype

next, t, nil = pairs (t)



Description

Returns the 'next' function, the table t, and nil, for use in a for loop.


t = { "hello", "world" }

for k, v in pairs (t) do
  print (k, v)   -- k is the key, v is the value
end 


Compare to ipairs which only traverses numerically-keyed entries.

Use the pairs function to traverse any table. The table will not necessarily be accessed in alphabetic (or any particular) order.

You must not add additional entries to the table during traversal. Doing so is undefined (that is, the script may crash or loop).

You are permitted to delete items from the table during traversal. In other words, if you find an item you want to delete you may assign nil to it, to delete it.



See Also ...

Topics

DOC_lua_base Lua base functions
DOC_lua_bc Lua bc (big number) functions
DOC_lua_bit Lua bit manipulation functions
DOC_lua_coroutines Lua coroutine functions
DOC_lua_debug Lua debug functions
DOC_lua_io Lua io functions
DOC_lua_math Lua math functions
DOC_lua_os Lua os functions
DOC_lua_package Lua package functions
DOC_lua_rex Lua PCRE regular expression functions
DOC_lua Lua script extensions
DOC_lua_string Lua string functions
DOC_lua_tables Lua table functions
DOC_lua_utils Lua utilities
DOC_scripting Scripting

Lua functions

LUA_assert assert (Asserts that condition is not nil and not false)
LUA_collectgarbage collectgarbage (Collects garbage)
LUA_dofile dofile (Executes a Lua file)
LUA_error error (Raises an error message)
LUA_gcinfo gcinfo (Returns amount of dynamic memory in use)
LUA_getfenv getfenv (Returns the current environment table)
LUA_getmetatable getmetatable (Returns the metatable for the object)
LUA_ipairs ipairs (Iterates over a numerically keyed table)
LUA_load load (Loads a chunk by calling a function repeatedly)
LUA_loadfile loadfile (Loads a Lua file and parses it)
LUA_loadlib loadlib (Loads a DLL (obsolete in Lua 5.1))
LUA_loadstring loadstring (Compiles a string of Lua code)
LUA_module module (Creates a Lua module)
LUA_next next (Returns next key / value pair in a table)
LUA_pcall pcall (Calls a function in protected mode)
LUA_print print (Prints its arguments)
LUA_rawequal rawequal (Compares two values for equality without invoking metamethods)
LUA_rawget rawget (Gets the value of a table item without invoking metamethods)
LUA_rawset rawset (Sets the value of a table item without invoking metamethods)
LUA_require require (Loads a module)
LUA_select select (Returns items in a list)
LUA_setfenv setfenv (Sets a function's environment)
LUA_setmetatable setmetatable (Sets the metatable for a table)
LUA_tonumber tonumber (Converts a string (of the given base) to a number)
LUA_tostring tostring (Converts its argument to a string)
LUA_type type (Returns the type of a variable)
LUA_unpack unpack (Unpacks a table into individual items)
LUA_xpcall xpcall (Calls a function with a custom error handler)

(Help topic: lua=pairs)

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