Summary
Returns the size of a numerically-keyed table
Prototype
n = table.getn (t)
Description
Returns the size of the table using the rules described at the start of this page.
A table's size (which is only relevant for "numeric" indexed tables) is one less than the first integer index with a nil value. If the table has "holes" in it - that is, numeric keys with gaps in the sequence - then the table size is not guaranteed to be the the last gap. Lua does a binary search to try to find a gap, it does not necessarily find the first or last one.
table.getn { "the", "quick", "brown", "fox", name = "Nick" } --> 4
Note that the length here is 4 and not 5, because the non-numeric entry (name = "Nick") is not considered to be part of the table's "length".
You can also use #t to find the length of a table.
# { "the", "quick", "brown", "fox", name = "Nick" } --> 4
Contrast to table.maxn which finds the highest key by a linear scan (and is therefore slower).
See Also ...
Lua functions
table.concat - Concatenates table items together into a string
table.foreach - Applies a function to each item in a table
table.foreachi - Applies a function to each item in a numerically-keyed table
table.insert - Inserts a new item into a numerically-keyed table
table.maxn - Returns the highest numeric key in the table
table.remove - Removes an item from a numerically-keyed table
table.setn - Sets the size of a table (obsolete)
table.sort - Sorts a table
Topics
Lua base functions
Lua bc (big number) functions
Lua bit manipulation functions
Lua coroutine functions
Lua debug functions
Lua io functions
Lua LPEG library
Lua math functions
Lua os functions
Lua package functions
Lua PCRE regular expression functions
Lua script extensions
Lua string functions
Lua syntax
Lua table functions
Lua utilities
Scripting
Scripting callbacks - plugins
(Help topic: lua=table.getn)