Module:TableTools/doc
This is the documentation page for Module:TableTools
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This module includes a number of functions for dealing with Lua tables. It is a meta-module, meant to be called from other Lua modules, and should not be called directly from #invoke.
Loading the module
To use any of the functions, first you must load the module.
<syntaxhighlight lang="lua"> local TableTools = require('Module:TableTools') </syntaxhighlight>
isPositiveInteger
<syntaxhighlight lang="lua"> TableTools.isPositiveInteger(value) </syntaxhighlight>
Returns true
if value
is a positive integer, and false
if not. Although it doesn't operate on tables, it is included here as it is useful for determining whether a given table key is in the array part or the hash part of a table.
isNan
<syntaxhighlight lang="lua"> TableTools.isNan(value) </syntaxhighlight>
Returns true
if value
is a NaN value, and false
if not. Although it doesn't operate on tables, it is included here as it is useful for determining whether a value can be a valid table key. (Lua will generate an error if a NaN value is used as a table key.)
shallowClone
<syntaxhighlight lang="lua"> TableTools.shallowClone(t) </syntaxhighlight>
Returns a clone of a table. The value returned is a new table, but all subtables and functions are shared. Metamethods are respected, but the returned table will have no metatable of its own. If you want to make a new table with no shared subtables and with metatables transferred, you can use mw.clone
instead. If you want to make a new table with no shared subtables and without metatables transferred, use deepCopy
with the noMetatable
option.
removeDuplicates
<syntaxhighlight lang="lua"> TableTools.removeDuplicates(t) </syntaxhighlight>
Removes duplicate values from an array. This function is only designed to work with standard arrays: keys that are not positive integers are ignored, as are all values after the first nil
value. (For arrays containing nil
values, you can use compressSparseArray
first.) The function tries to preserve the order of the array: the earliest non-unique value is kept, and all subsequent duplicate values are removed. For example, for the table <syntaxhighlight lang="lua" class="" id="" style="" inline="1">{5, 4, 4, 3, 4, 2, 2, 1}</syntaxhighlight> removeDuplicates
will return <syntaxhighlight lang="lua" class="" id="" style="" inline="1">{5, 4, 3, 2, 1}</syntaxhighlight>.
numKeys
<syntaxhighlight lang="lua"> TableTools.numKeys(t) </syntaxhighlight>
Takes a table t
and returns an array containing the numbers of any positive integer keys that have non-nil values, sorted in numerical order. For example, for the table <syntaxhighlight lang="lua" class="" id="" style="" inline="1">{'foo', nil, 'bar', 'baz', a = 'b'}</syntaxhighlight>, numKeys
will return <syntaxhighlight lang="lua" class="" id="" style="" inline="1">{1, 3, 4}</syntaxhighlight>.
affixNums
<syntaxhighlight lang="lua"> TableTools.affixNums(t, prefix, suffix) </syntaxhighlight>
Takes a table t
and returns an array containing the numbers of keys with the optional prefix prefix
and the optional suffix suffix
. For example, for the table <syntaxhighlight lang="lua" class="" id="" style="" inline="1">{a1 = 'foo', a3 = 'bar', a6 = 'baz'}</syntaxhighlight> and the prefix 'a'
, affixNums
will return <syntaxhighlight lang="lua" class="" id="" style="" inline="1">{1, 3, 6}</syntaxhighlight>. All characters in prefix
and suffix
are interpreted literally.
numData
<syntaxhighlight lang="lua"> TableTools.numData(t, compress) </syntaxhighlight>
Given a table with keys like "foo1"
, "bar1"
, "foo2"
, and "baz2"
, returns a table of subtables in the format <syntaxhighlight lang="lua" class="" id="" style="" inline="1">{ [1] = {foo = 'text', bar = 'text'}, [2] = {foo = 'text', baz = 'text'} }</syntaxhighlight>. Keys that don't end with an integer are stored in a subtable named "other"
. The compress option compresses the table so that it can be iterated over with ipairs
.
compressSparseArray
<syntaxhighlight lang="lua"> TableTools.compressSparseArray(t) </syntaxhighlight>
Takes an array t
with one or more nil values, and removes the nil values while preserving the order, so that the array can be safely traversed with ipairs
. Any keys that are not positive integers are removed. For example, for the table <syntaxhighlight lang="lua" class="" id="" style="" inline="1">{1, nil, foo = 'bar', 3, 2}</syntaxhighlight>, compressSparseArray
will return <syntaxhighlight lang="lua" class="" id="" style="" inline="1">{1, 3, 2}</syntaxhighlight>.
sparseIpairs
<syntaxhighlight lang="lua"> TableTools.sparseIpairs(t) </syntaxhighlight>
This is an iterator function for traversing a sparse array t
. It is similar to ipairs
, but will continue to iterate until the highest numerical key, whereas ipairs
may stop after the first nil
value. Any keys that are not positive integers are ignored.
Usually sparseIpairs
is used in a generic for
loop.
<syntaxhighlight lang="lua"> for i, v in TableTools.sparseIpairs(t) do
-- code block
end </syntaxhighlight>
Note that sparseIpairs
uses the pairs
function in its implementation. Although some table keys appear to be ignored, all table keys are accessed when it is run.
size
<syntaxhighlight lang="lua"> TableTools.size(t) </syntaxhighlight>
Finds the size of a key/value pair table. For example, for the table <syntaxhighlight lang="lua" class="" id="" style="" inline="1">{foo = 'foo', bar = 'bar'}</syntaxhighlight>, size
will return 2
. The function will also work on arrays, but for arrays it is more efficient to use the #
operator. Note that to find the table size, this function uses the pairs
function to iterate through all of the table keys.
keysToList
<syntaxhighlight lang="lua"> TableTools.keysToList(t, keySort, checked) </syntaxhighlight>
Returns a list of the keys in a table, sorted using either a default comparison function or a custom keySort
function, which follows the same rules as the comp
function supplied to table.sort
. If keySort
is false
, no sorting is done. Set checked
to true
to skip the internal type checking.
sortedPairs
<syntaxhighlight lang="lua"> TableTools.sortedPairs(t, keySort) </syntaxhighlight>
Iterates through a table, with the keys sorted using the keysToList
function. If there are only numerical keys, sparseIpairs
is probably more efficient.
isArray
<syntaxhighlight lang="lua"> TableTools.isArray(value) </syntaxhighlight>
Returns true
if value
is a table and all keys are consecutive integers starting at 1.
isArrayLike
<syntaxhighlight lang="lua"> TableTools.isArrayLike(value) </syntaxhighlight>
Returns true
if value
is iterable and all keys are consecutive integers starting at 1.
invert
<syntaxhighlight lang="lua"> TableTools.invert(arr) </syntaxhighlight>
Transposes the keys and values in an array. For example, <syntaxhighlight lang="lua" class="" id="" style="" inline="1">invert{ "a", "b", "c" }</syntaxhighlight> yields <syntaxhighlight lang="lua" class="" id="" style="" inline="1">{ a=1, b=2, c=3 }</syntaxhighlight>.
listToSet
<syntaxhighlight lang="lua"> TableTools.listToSet(arr) </syntaxhighlight>
Creates a set from the array part of the table arr
. Indexing the set by any of the values of the array returns true
. For example, <syntaxhighlight lang="lua" class="" id="" style="" inline="1">listToSet{ "a", "b", "c" }</syntaxhighlight> yields <syntaxhighlight lang="lua" class="" id="" style="" inline="1">{ a=true, b=true, c=true }</syntaxhighlight>. See also Module:Lua set for more advanced ways to create a set.
deepCopy
<syntaxhighlight lang="lua"> TableTools.deepCopy(orig, noMetatable, alreadySeen) </syntaxhighlight>
Creates a copy of the table orig
. As with mw.clone
, all values that are not functions are duplicated and the identity of tables is preserved. If noMetatable
is true
, then the metatable (if any) is not copied. Can copy tables loaded with mw.loadData
.
Similar to mw.clone
, but mw.clone
cannot copy tables loaded with mw.loadData
and does not allow metatables not to be copied.
sparseConcat
<syntaxhighlight lang="lua"> TableTools.sparseConcat(t, sep, i, j) </syntaxhighlight>
Concatenates all values in the table that are indexed by a positive integer, in order. For example, <syntaxhighlight lang="lua" class="" id="" style="" inline="1">sparseConcat{ "a", nil, "c", "d" }</syntaxhighlight> yields <syntaxhighlight lang="lua" class="" id="" style="" inline="1">"acd"</syntaxhighlight> and <syntaxhighlight lang="lua" class="" id="" style="" inline="1">sparseConcat{ nil, "b", "c", "d" }</syntaxhighlight> yields <syntaxhighlight lang="lua" class="" id="" style="" inline="1">"bcd"</syntaxhighlight>.
length
<syntaxhighlight lang="lua"> TableTools.length(t, prefix) </syntaxhighlight>
Finds the length of an array or of a quasi-array with keys with an optional prefix
such as "data1", "data2", etc. It uses an exponential search algorithm to find the length, so as to use as few table lookups as possible.
This algorithm is useful for arrays that use metatables (e.g. frame.args) and for quasi-arrays. For normal arrays, just use the # operator, as it is implemented in C and will be quicker.
inArray
<syntaxhighlight lang="lua"> TableTools.inArray(arr, valueToFind) </syntaxhighlight>
Returns true
if valueToFind
is a member of the array arr
, and false
otherwise.