5.5 – Table Manipulation
This library provides generic functions for table manipulation. It provides all its functions inside the table table
.
Most functions in the table library assume that the table represents an array or a list. For these functions, when we talk about the “length” of a table we mean the result of the length operator.
table.concat (table [, sep [, i [, j]]])
Given an array where all elements are strings or numbers, returns table[i]..sep..table[i+1] ··· sep..table[j]
. The default value for sep
is the empty string, the default for i
is 1, and the default for j
is the length of the table. If i
is greater than j
, returns the empty string.
table.insert (table, [pos,] value)
Inserts element value
at position pos
in table
, shifting up other elements to open space, if necessary. The default value for pos
is n+1
, where n
is the length of the table (see §2.5.5), so that a call table.insert(t,x)
inserts x
at the end of table t
.
table.maxn (table)
Returns the largest positive numerical index of the given table, or zero if the table has no positive numerical indices. (To do its job this function does a linear traversal of the whole table.)
table.remove (table [, pos])
Removes from table
the element at position pos
, shifting down other elements to close the space, if necessary. Returns the value of the removed element. The default value for pos
is n
, where n
is the length of the table, so that a call table.remove(t)
removes the last element of table t
.
table.sort (table [, comp])
Sorts table elements in a given order, in-place, from table[1]
to table[n]
, where n
is the length of the table. If comp
is given, then it must be a function that receives two table elements, and returns true when the first is less than the second (so that not comp(a[i+1],a[i])
will be true after the sort). If comp
is not given, then the standard Lua operator <
is used instead.
The sort algorithm is not stable; that is, elements considered equal by the given order may have their relative positions changed by the sort.