Module:TableTools: Difference between revisions

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--[[
------------------------------------------------------------------------------------
------------------------------------------------------------------------------------
--                                   TableTools                                   --
--                               TableTools                                       --
--                                                                                --
--                                                                                --
-- This module includes a number of functions for dealing with Lua tables.        --
-- 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 --
-- It is a meta-module, meant to be called from other Lua modules, and should     --
-- be called directly from #invoke.                                               --
-- not be called directly from #invoke.                                           --
------------------------------------------------------------------------------------
------------------------------------------------------------------------------------
--]]


local libraryUtil = require('libraryUtil')
local libraryUtil = require('libraryUtil')
Line 17: Line 19:
local checkTypeMulti = libraryUtil.checkTypeMulti
local checkTypeMulti = libraryUtil.checkTypeMulti


--[[
------------------------------------------------------------------------------------
------------------------------------------------------------------------------------
-- isPositiveInteger
-- isPositiveInteger
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-- hash part of a table.
-- hash part of a table.
------------------------------------------------------------------------------------
------------------------------------------------------------------------------------
--]]
function p.isPositiveInteger(v)
function p.isPositiveInteger(v)
return type(v) == 'number' and v >= 1 and floor(v) == v and v < infinity
if type(v) == 'number' and v >= 1 and floor(v) == v and v < infinity then
return true
else
return false
end
end
end


--[[
------------------------------------------------------------------------------------
------------------------------------------------------------------------------------
-- isNan
-- isNan
--
--
-- This function returns true if the given number is a NaN value, and false if
-- This function returns true if the given number is a NaN value, and false
-- not. Although it doesn't operate on tables, it is included here as it is useful
-- if not. Although it doesn't operate on tables, it is included here as it is
-- for determining whether a value can be a valid table key. Lua will generate an
-- useful for determining whether a value can be a valid table key. Lua will
-- error if a NaN is used as a table key.
-- generate an error if a NaN is used as a table key.
------------------------------------------------------------------------------------
------------------------------------------------------------------------------------
--]]
function p.isNan(v)
function p.isNan(v)
return type(v) == 'number' and v ~= v
if type(v) == 'number' and tostring(v) == '-nan' then
return true
else
return false
end
end
end


--[[
------------------------------------------------------------------------------------
------------------------------------------------------------------------------------
-- shallowClone
-- shallowClone
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-- table will have no metatable of its own.
-- table will have no metatable of its own.
------------------------------------------------------------------------------------
------------------------------------------------------------------------------------
--]]
function p.shallowClone(t)
function p.shallowClone(t)
checkType('shallowClone', 1, t, 'table')
local ret = {}
local ret = {}
for k, v in pairs(t) do
for k, v in pairs(t) do
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end
end


--[[
------------------------------------------------------------------------------------
------------------------------------------------------------------------------------
-- removeDuplicates
-- removeDuplicates
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-- removed, but otherwise the array order is unchanged.
-- removed, but otherwise the array order is unchanged.
------------------------------------------------------------------------------------
------------------------------------------------------------------------------------
function p.removeDuplicates(arr)
--]]
checkType('removeDuplicates', 1, arr, 'table')
function p.removeDuplicates(t)
checkType('removeDuplicates', 1, t, 'table')
local isNan = p.isNan
local isNan = p.isNan
local ret, exists = {}, {}
local ret, exists = {}, {}
for _, v in ipairs(arr) do
for i, v in ipairs(t) do
if isNan(v) then
if isNan(v) then
-- NaNs can't be table keys, and they are also unique, so we don't need to check existence.
-- NaNs can't be table keys, and they are also unique, so we don't need to check existence.
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exists[v] = true
exists[v] = true
end
end
end
end
end
end
return ret
return ret
end
end


--[[
------------------------------------------------------------------------------------
------------------------------------------------------------------------------------
-- numKeys
-- numKeys
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-- keys that have non-nil values, sorted in numerical order.
-- keys that have non-nil values, sorted in numerical order.
------------------------------------------------------------------------------------
------------------------------------------------------------------------------------
--]]
function p.numKeys(t)
function p.numKeys(t)
checkType('numKeys', 1, t, 'table')
checkType('numKeys', 1, t, 'table')
local isPositiveInteger = p.isPositiveInteger
local isPositiveInteger = p.isPositiveInteger
local nums = {}
local nums = {}
for k in pairs(t) do
for k, v in pairs(t) do
if isPositiveInteger(k) then
if isPositiveInteger(k) then
nums[#nums + 1] = k
nums[#nums + 1] = k
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end
end


--[[
------------------------------------------------------------------------------------
------------------------------------------------------------------------------------
-- affixNums
-- affixNums
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-- This takes a table and returns an array containing the numbers of keys with the
-- This takes a table and returns an array containing the numbers of keys with the
-- specified prefix and suffix. For example, for the table
-- specified prefix and suffix. For example, for the table
-- {a1 = 'foo', a3 = 'bar', a6 = 'baz'} and the prefix "a", affixNums will return
-- {a1 = 'foo', a3 = 'bar', a6 = 'baz'} and the prefix "a", affixNums will
-- {1, 3, 6}.
-- return {1, 3, 6}.
------------------------------------------------------------------------------------
------------------------------------------------------------------------------------
--]]
function p.affixNums(t, prefix, suffix)
function p.affixNums(t, prefix, suffix)
checkType('affixNums', 1, t, 'table')
checkType('affixNums', 1, t, 'table')
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local function cleanPattern(s)
local function cleanPattern(s)
-- Cleans a pattern so that the magic characters ()%.[]*+-?^$ are interpreted literally.
-- Cleans a pattern so that the magic characters ()%.[]*+-?^$ are interpreted literally.
return s:gsub('([%(%)%%%.%[%]%*%+%-%?%^%$])', '%%%1')
s = s:gsub('([%(%)%%%.%[%]%*%+%-%?%^%$])', '%%%1')
return s
end
end


Line 126: Line 148:


local nums = {}
local nums = {}
for k in pairs(t) do
for k, v in pairs(t) do
if type(k) == 'string' then
if type(k) == 'string' then
local num = mw.ustring.match(k, pattern)
local num = mw.ustring.match(k, pattern)
if num then
if num then
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end
end


--[[
------------------------------------------------------------------------------------
------------------------------------------------------------------------------------
-- numData
-- numData
--
--
-- Given a table with keys like {"foo1", "bar1", "foo2", "baz2"}, returns a table
-- Given a table with keys like ("foo1", "bar1", "foo2", "baz2"), returns a table
-- of subtables in the format
-- of subtables in the format  
-- {[1] = {foo = 'text', bar = 'text'}, [2] = {foo = 'text', baz = 'text'}}.
-- { [1] = {foo = 'text', bar = 'text'}, [2] = {foo = 'text', baz = 'text'} }
-- Keys that don't end with an integer are stored in a subtable named "other". The
-- Keys that don't end with an integer are stored in a subtable named "other".
-- compress option compresses the table so that it can be iterated over with
-- The compress option compresses the table so that it can be iterated over with
-- ipairs.
-- ipairs.
------------------------------------------------------------------------------------
------------------------------------------------------------------------------------
--]]
function p.numData(t, compress)
function p.numData(t, compress)
checkType('numData', 1, t, 'table')
checkType('numData', 1, t, 'table')
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end
end


--[[
------------------------------------------------------------------------------------
------------------------------------------------------------------------------------
-- compressSparseArray
-- compressSparseArray
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-- ipairs.
-- ipairs.
------------------------------------------------------------------------------------
------------------------------------------------------------------------------------
--]]
function p.compressSparseArray(t)
function p.compressSparseArray(t)
checkType('compressSparseArray', 1, t, 'table')
checkType('compressSparseArray', 1, t, 'table')
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end
end


--[[
------------------------------------------------------------------------------------
------------------------------------------------------------------------------------
-- sparseIpairs
-- sparseIpairs
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-- handle nil values.
-- handle nil values.
------------------------------------------------------------------------------------
------------------------------------------------------------------------------------
--]]
function p.sparseIpairs(t)
function p.sparseIpairs(t)
checkType('sparseIpairs', 1, t, 'table')
checkType('sparseIpairs', 1, t, 'table')
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end
end


--[[
------------------------------------------------------------------------------------
------------------------------------------------------------------------------------
-- size
-- size
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-- but for arrays it is more efficient to use the # operator.
-- but for arrays it is more efficient to use the # operator.
------------------------------------------------------------------------------------
------------------------------------------------------------------------------------
--]]
function p.size(t)
function p.size(t)
checkType('size', 1, t, 'table')
checkType('size', 1, t, 'table')
local i = 0
local i = 0
for _ in pairs(t) do
for k in pairs(t) do
i = i + 1
i = i + 1
end
end
return i
return i
end
end


local function defaultKeySort(item1, item2)
local function defaultKeySort(item1, item2)
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if type1 ~= type2 then
if type1 ~= type2 then
return type1 < type2
return type1 < type2
elseif type1 == 'table' or type1 == 'boolean' or type1 == 'function' then
else -- This will fail with table, boolean, function.
return tostring(item1) < tostring(item2)
else
return item1 < item2
return item1 < item2
end
end
end
end
------------------------------------------------------------------------------------
 
-- keysToList
--[[
--
Returns a list of the keys in a table, sorted using either a default
-- Returns an array of the keys in a table, sorted using either a default
comparison function or a custom keySort function.
-- comparison function or a custom keySort function.
]]
------------------------------------------------------------------------------------
function p.keysToList(t, keySort, checked)
function p.keysToList(t, keySort, checked)
if not checked then
if not checked then
checkType('keysToList', 1, t, 'table')
checkType('keysToList', 1, t, 'table')
checkTypeMulti('keysToList', 2, keySort, {'function', 'boolean', 'nil'})
checkTypeMulti('keysToList', 2, keySort, { 'function', 'boolean', 'nil' })
end
end
 
local arr = {}
local list = {}
local index = 1
local index = 1
for k in pairs(t) do
for key, value in pairs(t) do
arr[index] = k
list[index] = key
index = index + 1
index = index + 1
end
end
 
if keySort ~= false then
if keySort ~= false then
keySort = type(keySort) == 'function' and keySort or defaultKeySort
keySort = type(keySort) == 'function' and keySort or defaultKeySort
table.sort(arr, keySort)
table.sort(list, keySort)
end
end
 
return arr
return list
end
end


------------------------------------------------------------------------------------
--[[
-- sortedPairs
Iterates through a table, with the keys sorted using the keysToList function.
--
If there are only numerical keys, sparseIpairs is probably more efficient.
-- Iterates through a table, with the keys sorted using the keysToList function.
]]
-- If there are only numerical keys, sparseIpairs is probably more efficient.
------------------------------------------------------------------------------------
function p.sortedPairs(t, keySort)
function p.sortedPairs(t, keySort)
checkType('sortedPairs', 1, t, 'table')
checkType('sortedPairs', 1, t, 'table')
checkType('sortedPairs', 2, keySort, 'function', true)
checkType('sortedPairs', 2, keySort, 'function', true)
 
local arr = p.keysToList(t, keySort, true)
local list = p.keysToList(t, keySort, true)
 
local i = 0
local i = 0
return function ()
return function()
i = i + 1
i = i + 1
local key = arr[i]
local key = list[i]
if key ~= nil then
if key ~= nil then
return key, t[key]
return key, t[key]
Line 293: Line 321:
end
end


------------------------------------------------------------------------------------
--[[
-- isArray
Returns true if all keys in the table are consecutive integers starting at 1.
--
--]]
-- Returns true if the given value is a table and all keys are consecutive
function p.isArray(t)
-- integers starting at 1.
checkType("isArray", 1, t, "table")
------------------------------------------------------------------------------------
function p.isArray(v)
if type(v) ~= 'table' then
return false
end
local i = 0
local i = 0
for _ in pairs(v) do
for k, v in pairs(t) do
i = i + 1
if v[i] == nil then
return false
end
end
return true
end
 
------------------------------------------------------------------------------------
-- isArrayLike
--
-- Returns true if the given value is iterable and all keys are consecutive
-- integers starting at 1.
------------------------------------------------------------------------------------
function p.isArrayLike(v)
if not pcall(pairs, v) then
return false
end
local i = 0
for _ in pairs(v) do
i = i + 1
i = i + 1
if v[i] == nil then
if t[i] == nil then
return false
return false
end
end
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end
end


------------------------------------------------------------------------------------
-- { "a", "b", "c" } -> { a = 1, b = 2, c = 3 }
-- invert
function p.invert(array)
--
checkType("invert", 1, array, "table")
-- Transposes the keys and values in an array. For example, {"a", "b", "c"} ->
-- {a = 1, b = 2, c = 3}. Duplicates are not supported (result values refer to
-- the index of the last duplicate) and NaN values are ignored.
------------------------------------------------------------------------------------
function p.invert(arr)
checkType("invert", 1, arr, "table")
local isNan = p.isNan
local map = {}
local map = {}
for i, v in ipairs(arr) do
for i, v in ipairs(array) do
if not isNan(v) then
map[v] = i
map[v] = i
end
end
end
 
return map
return map
end
end


------------------------------------------------------------------------------------
--[[
-- listToSet
{ "a", "b", "c" } -> { ["a"] = true, ["b"] = true, ["c"] = true }
--
--]]
-- Creates a set from the array part of the table. Indexing the set by any of the
function p.listToSet(t)
-- values of the array returns true. For example, {"a", "b", "c"} ->
checkType("listToSet", 1, t, "table")
-- {a = true, b = true, c = true}. NaN values are ignored as Lua considers them
-- never equal to any value (including other NaNs or even themselves).
------------------------------------------------------------------------------------
function p.listToSet(arr)
checkType("listToSet", 1, arr, "table")
local isNan = p.isNan
local set = {}
local set = {}
for _, v in ipairs(arr) do
for _, item in ipairs(t) do
if not isNan(v) then
set[item] = true
set[v] = true
end
end
end
 
return set
return set
end
end


------------------------------------------------------------------------------------
--[[
-- deepCopy
Recursive deep copy function.
--
Preserves identities of subtables.
-- Recursive deep copy function. Preserves identities of subtables.
------------------------------------------------------------------------------------
]]
local function _deepCopy(orig, includeMetatable, already_seen)
local function _deepCopy(orig, includeMetatable, already_seen)
-- Stores copies of tables indexed by the original table.
-- Stores copies of tables indexed by the original table.
already_seen = already_seen or {}
already_seen = already_seen or {}
 
local copy = already_seen[orig]
local copy = already_seen[orig]
if copy ~= nil then
if copy ~= nil then
return copy
return copy
end
end
 
if type(orig) == 'table' then
if type(orig) == 'table' then
copy = {}
copy = {}
for orig_key, orig_value in pairs(orig) do
for orig_key, orig_value in pairs(orig) do
copy[_deepCopy(orig_key, includeMetatable, already_seen)] = _deepCopy(orig_value, includeMetatable, already_seen)
copy[deepcopy(orig_key, includeMetatable, already_seen)] = deepcopy(orig_value, includeMetatable, already_seen)
end
end
already_seen[orig] = copy
already_seen[orig] = copy
 
if includeMetatable then
if includeMetatable then
local mt = getmetatable(orig)
local mt = getmetatable(orig)
if mt ~= nil then
if mt ~= nil then
local mt_copy = _deepCopy(mt, includeMetatable, already_seen)
local mt_copy = deepcopy(mt, includeMetatable, already_seen)
setmetatable(copy, mt_copy)
setmetatable(copy, mt_copy)
already_seen[mt] = mt_copy
already_seen[mt] = mt_copy
Line 411: Line 400:
function p.deepCopy(orig, noMetatable, already_seen)
function p.deepCopy(orig, noMetatable, already_seen)
checkType("deepCopy", 3, already_seen, "table", true)
checkType("deepCopy", 3, already_seen, "table", true)
return _deepCopy(orig, not noMetatable, already_seen)
return _deepCopy(orig, not noMetatable, already_seen)
end
end


------------------------------------------------------------------------------------
--[[
-- sparseConcat
Concatenates all values in the table that are indexed by a number, in order.
--
sparseConcat{ a, nil, c, d }  =>  "acd"
-- Concatenates all values in the table that are indexed by a number, in order.
sparseConcat{ nil, b, c, d }  =>  "bcd"
-- sparseConcat{a, nil, c, d}  =>  "acd"
]]
-- sparseConcat{nil, b, c, d}  =>  "bcd"
------------------------------------------------------------------------------------
function p.sparseConcat(t, sep, i, j)
function p.sparseConcat(t, sep, i, j)
local arr = {}
local list = {}
 
local arr_i = 0
local list_i = 0
for _, v in p.sparseIpairs(t) do
for _, v in p.sparseIpairs(t) do
arr_i = arr_i + 1
list_i = list_i + 1
arr[arr_i] = v
list[list_i] = v
end
end
 
return table.concat(arr, sep, i, j)
return table.concat(list, sep, i, j)
end
end


------------------------------------------------------------------------------------
--[[
-- length
-- This returns the length of a table, or the first integer key n counting from
--
-- 1 such that t[n + 1] is nil. It is similar to the operator #, but may return
-- Finds the length of an array, or of a quasi-array with keys such as "data1",
-- a different value when there are gaps in the array portion of the table.
-- "data2", etc., using an exponential search algorithm. It is similar to the
-- Intended to be used on data loaded with mw.loadData. For other tables, use #.
-- operator #, but may return a different value when there are gaps in the array
-- Note: #frame.args in frame object always be set to 0, regardless of  
-- portion of the table. Intended to be used on data loaded with mw.loadData. For
-- the number of unnamed template parameters, so use this function for
-- other tables, use #.
-- frame.args.
-- Note: #frame.args in frame object always be set to 0, regardless of the number
--]]
-- of unnamed template parameters, so use this function for frame.args.
function p.length(t)
------------------------------------------------------------------------------------
local i = 1
function p.length(t, prefix)
while t[i] ~= nil do
-- requiring module inline so that [[Module:Exponential search]] which is
i = i + 1
-- only needed by this one function doesn't get millions of transclusions
end
local expSearch = require("Module:Exponential search")
return i - 1
checkType('length', 1, t, 'table')
checkType('length', 2, prefix, 'string', true)
return expSearch(function (i)
local key
if prefix then
key = prefix .. tostring(i)
else
key = i
end
return t[key] ~= nil
end) or 0
end
end


------------------------------------------------------------------------------------
-- inArray
--
-- Returns true if valueToFind is a member of the array, and false otherwise.
------------------------------------------------------------------------------------
function p.inArray(arr, valueToFind)
function p.inArray(arr, valueToFind)
checkType("inArray", 1, arr, "table")
checkType("inArray", 1, arr, "table")
-- if valueToFind is nil, error?
-- if valueToFind is nil, error?
 
for _, v in ipairs(arr) do
for _, v in ipairs(arr) do
if v == valueToFind then
if v == valueToFind then
Line 475: Line 448:
end
end
end
end
return false
return false
end
end


return p
return p

Latest revision as of 18:38, 19 April 2023

warning Warning:Do not edit. This page is maintained by an automated tool. All edits should be done at mediawiki.org. (translate this warning)

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.

Module Quality

Module:TableTools success: 9, error: 0, skipped: 0
Module:TableTools/sandbox success: 9, error: 0, skipped: 0

Loading the module

To use any of the functions, first you must load the module.

<syntaxhighlight lang="lua"> local TableTools = require('Module:TableTools') </syntaxhighlight>

Functions

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">{5, 4, 4, 3, 4, 2, 2, 1}</syntaxhighlight> removeDuplicates will return <syntaxhighlight lang="lua">{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">{'foo', nil, 'bar', 'baz', a = 'b'}</syntaxhighlight>, numKeys will return <syntaxhighlight lang="lua">{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">{a1 = 'foo', a3 = 'bar', a6 = 'baz'}</syntaxhighlight> and the prefix 'a', affixNums will return <syntaxhighlight lang="lua">{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">{ [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">{1, nil, foo = 'bar', 3, 2}</syntaxhighlight>, compressSparseArray will return <syntaxhighlight lang="lua">{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">{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) </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 .

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(t) </syntaxhighlight>

Returns true if all keys in the table are consecutive integers starting at 1.

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 in arr returns true.

<syntaxhighlight lang="lua"> local set = TableTools.listToSet { "a", "b", "c" } assert(set["a"] === true) </syntaxhighlight>

invert

<syntaxhighlight lang="lua"> TableTools.invert(t) </syntaxhighlight>

Transposes the keys and values in an array. For example, invert{ "a", "b", "c" } yields { a = 1, b = 2, c = 3 }.

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) </syntaxhighlight>

Concatenates all values in the table that are indexed by a positive integer, in order.

length

<syntaxhighlight lang="lua"> TableTools.length(t) </syntaxhighlight>

Returns the length of a table, or the first integer key n counting from 0 such that t[n + 1] is nil. It is similar to the operator #, but may return a different value when there are gaps in the array portion of the table. Intended to be used on data loaded with mw.loadData and on frame.args. Both use a metatable such that #mw.loadData("module:...") and #frame.args don't work correctly. For other tables, use #.

inArray

<syntaxhighlight lang="lua"> TableTools.inArray(arr, valueToFind) </syntaxhighlight>

Returns <syntaxhighlight lang="lua" inline>true</syntaxhighlight> if valueToFind is a member of the array arr, and <syntaxhighlight lang="lua" inline>false</syntaxhighlight> otherwise.


--[[
------------------------------------------------------------------------------------
--                               TableTools                                       --
--                                                                                --
-- 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.                                           --
------------------------------------------------------------------------------------
--]]

local libraryUtil = require('libraryUtil')

local p = {}

-- Define often-used variables and functions.
local floor = math.floor
local infinity = math.huge
local checkType = libraryUtil.checkType
local checkTypeMulti = libraryUtil.checkTypeMulti

--[[
------------------------------------------------------------------------------------
-- isPositiveInteger
--
-- This function returns true if the given 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.
------------------------------------------------------------------------------------
--]]
function p.isPositiveInteger(v)
	if type(v) == 'number' and v >= 1 and floor(v) == v and v < infinity then
		return true
	else
		return false
	end
end

--[[
------------------------------------------------------------------------------------
-- isNan
--
-- This function returns true if the given number 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 is used as a table key.
------------------------------------------------------------------------------------
--]]
function p.isNan(v)
	if type(v) == 'number' and tostring(v) == '-nan' then
		return true
	else
		return false
	end
end

--[[
------------------------------------------------------------------------------------
-- shallowClone
--
-- This 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.
------------------------------------------------------------------------------------
--]]
function p.shallowClone(t)
	local ret = {}
	for k, v in pairs(t) do
		ret[k] = v
	end
	return ret
end

--[[
------------------------------------------------------------------------------------
-- removeDuplicates
--
-- This removes duplicate values from an array. Non-positive-integer keys are
-- ignored. The earliest value is kept, and all subsequent duplicate values are
-- removed, but otherwise the array order is unchanged.
------------------------------------------------------------------------------------
--]]
function p.removeDuplicates(t)
	checkType('removeDuplicates', 1, t, 'table')
	local isNan = p.isNan
	local ret, exists = {}, {}
	for i, v in ipairs(t) do
		if isNan(v) then
			-- NaNs can't be table keys, and they are also unique, so we don't need to check existence.
			ret[#ret + 1] = v
		else
			if not exists[v] then
				ret[#ret + 1] = v
				exists[v] = true
			end
		end	
	end
	return ret
end			

--[[
------------------------------------------------------------------------------------
-- numKeys
--
-- This takes a table and returns an array containing the numbers of any numerical
-- keys that have non-nil values, sorted in numerical order.
------------------------------------------------------------------------------------
--]]
function p.numKeys(t)
	checkType('numKeys', 1, t, 'table')
	local isPositiveInteger = p.isPositiveInteger
	local nums = {}
	for k, v in pairs(t) do
		if isPositiveInteger(k) then
			nums[#nums + 1] = k
		end
	end
	table.sort(nums)
	return nums
end

--[[
------------------------------------------------------------------------------------
-- affixNums
--
-- This takes a table and returns an array containing the numbers of keys with the
-- specified prefix and suffix. For example, for the table
-- {a1 = 'foo', a3 = 'bar', a6 = 'baz'} and the prefix "a", affixNums will
-- return {1, 3, 6}.
------------------------------------------------------------------------------------
--]]
function p.affixNums(t, prefix, suffix)
	checkType('affixNums', 1, t, 'table')
	checkType('affixNums', 2, prefix, 'string', true)
	checkType('affixNums', 3, suffix, 'string', true)

	local function cleanPattern(s)
		-- Cleans a pattern so that the magic characters ()%.[]*+-?^$ are interpreted literally.
		s = s:gsub('([%(%)%%%.%[%]%*%+%-%?%^%$])', '%%%1')
		return s
	end

	prefix = prefix or ''
	suffix = suffix or ''
	prefix = cleanPattern(prefix)
	suffix = cleanPattern(suffix)
	local pattern = '^' .. prefix .. '([1-9]%d*)' .. suffix .. '$'

	local nums = {}
	for k, v in pairs(t) do
		if type(k) == 'string' then			
			local num = mw.ustring.match(k, pattern)
			if num then
				nums[#nums + 1] = tonumber(num)
			end
		end
	end
	table.sort(nums)
	return nums
end

--[[
------------------------------------------------------------------------------------
-- numData
--
-- Given a table with keys like ("foo1", "bar1", "foo2", "baz2"), returns a table
-- of subtables in the format 
-- { [1] = {foo = 'text', bar = 'text'}, [2] = {foo = 'text', baz = 'text'} }
-- 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.
------------------------------------------------------------------------------------
--]]
function p.numData(t, compress)
	checkType('numData', 1, t, 'table')
	checkType('numData', 2, compress, 'boolean', true)
	local ret = {}
	for k, v in pairs(t) do
		local prefix, num = mw.ustring.match(tostring(k), '^([^0-9]*)([1-9][0-9]*)$')
		if num then
			num = tonumber(num)
			local subtable = ret[num] or {}
			if prefix == '' then
				-- Positional parameters match the blank string; put them at the start of the subtable instead.
				prefix = 1
			end
			subtable[prefix] = v
			ret[num] = subtable
		else
			local subtable = ret.other or {}
			subtable[k] = v
			ret.other = subtable
		end
	end
	if compress then
		local other = ret.other
		ret = p.compressSparseArray(ret)
		ret.other = other
	end
	return ret
end

--[[
------------------------------------------------------------------------------------
-- compressSparseArray
--
-- This takes an array 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.
------------------------------------------------------------------------------------
--]]
function p.compressSparseArray(t)
	checkType('compressSparseArray', 1, t, 'table')
	local ret = {}
	local nums = p.numKeys(t)
	for _, num in ipairs(nums) do
		ret[#ret + 1] = t[num]
	end
	return ret
end

--[[
------------------------------------------------------------------------------------
-- sparseIpairs
--
-- This is an iterator for sparse arrays. It can be used like ipairs, but can
-- handle nil values.
------------------------------------------------------------------------------------
--]]
function p.sparseIpairs(t)
	checkType('sparseIpairs', 1, t, 'table')
	local nums = p.numKeys(t)
	local i = 0
	local lim = #nums
	return function ()
		i = i + 1
		if i <= lim then
			local key = nums[i]
			return key, t[key]
		else
			return nil, nil
		end
	end
end

--[[
------------------------------------------------------------------------------------
-- size
--
-- This returns the size of a key/value pair table. It will also work on arrays,
-- but for arrays it is more efficient to use the # operator.
------------------------------------------------------------------------------------
--]]

function p.size(t)
	checkType('size', 1, t, 'table')
	local i = 0
	for k in pairs(t) do
		i = i + 1
	end
	return i
end


local function defaultKeySort(item1, item2)
	-- "number" < "string", so numbers will be sorted before strings.
	local type1, type2 = type(item1), type(item2)
	if type1 ~= type2 then
		return type1 < type2
	else -- This will fail with table, boolean, function.
		return item1 < item2
	end
end

--[[
	Returns a list of the keys in a table, sorted using either a default
	comparison function or a custom keySort function.
]]
function p.keysToList(t, keySort, checked)
	if not checked then
		checkType('keysToList', 1, t, 'table')
		checkTypeMulti('keysToList', 2, keySort, { 'function', 'boolean', 'nil' })
	end
	
	local list = {}
	local index = 1
	for key, value in pairs(t) do
		list[index] = key
		index = index + 1
	end
	
	if keySort ~= false then
		keySort = type(keySort) == 'function' and keySort or defaultKeySort
		
		table.sort(list, keySort)
	end
	
	return list
end

--[[
	Iterates through a table, with the keys sorted using the keysToList function.
	If there are only numerical keys, sparseIpairs is probably more efficient.
]]
function p.sortedPairs(t, keySort)
	checkType('sortedPairs', 1, t, 'table')
	checkType('sortedPairs', 2, keySort, 'function', true)
	
	local list = p.keysToList(t, keySort, true)
	
	local i = 0
	return function()
		i = i + 1
		local key = list[i]
		if key ~= nil then
			return key, t[key]
		else
			return nil, nil
		end
	end
end

--[[
	Returns true if all keys in the table are consecutive integers starting at 1.
--]]
function p.isArray(t)
	checkType("isArray", 1, t, "table")
	
	local i = 0
	for k, v in pairs(t) do
		i = i + 1
		if t[i] == nil then
			return false
		end
	end
	return true
end

-- { "a", "b", "c" } -> { a = 1, b = 2, c = 3 }
function p.invert(array)
	checkType("invert", 1, array, "table")
	
	local map = {}
	for i, v in ipairs(array) do
		map[v] = i
	end
	
	return map
end

--[[
	{ "a", "b", "c" } -> { ["a"] = true, ["b"] = true, ["c"] = true }
--]]
function p.listToSet(t)
	checkType("listToSet", 1, t, "table")
	
	local set = {}
	for _, item in ipairs(t) do
		set[item] = true
	end
	
	return set
end

--[[
	Recursive deep copy function.
	Preserves identities of subtables.
	
]]
local function _deepCopy(orig, includeMetatable, already_seen)
	-- Stores copies of tables indexed by the original table.
	already_seen = already_seen or {}
	
	local copy = already_seen[orig]
	if copy ~= nil then
		return copy
	end
	
	if type(orig) == 'table' then
		copy = {}
		for orig_key, orig_value in pairs(orig) do
			copy[deepcopy(orig_key, includeMetatable, already_seen)] = deepcopy(orig_value, includeMetatable, already_seen)
		end
		already_seen[orig] = copy
		
		if includeMetatable then
			local mt = getmetatable(orig)
			if mt ~= nil then
				local mt_copy = deepcopy(mt, includeMetatable, already_seen)
				setmetatable(copy, mt_copy)
				already_seen[mt] = mt_copy
			end
		end
	else -- number, string, boolean, etc
		copy = orig
	end
	return copy
end

function p.deepCopy(orig, noMetatable, already_seen)
	checkType("deepCopy", 3, already_seen, "table", true)
	
	return _deepCopy(orig, not noMetatable, already_seen)
end

--[[
	Concatenates all values in the table that are indexed by a number, in order.
	sparseConcat{ a, nil, c, d }  =>  "acd"
	sparseConcat{ nil, b, c, d }  =>  "bcd"
]]
function p.sparseConcat(t, sep, i, j)
	local list = {}
	
	local list_i = 0
	for _, v in p.sparseIpairs(t) do
		list_i = list_i + 1
		list[list_i] = v
	end
	
	return table.concat(list, sep, i, j)
end

--[[
-- This returns the length of a table, or the first integer key n counting from
-- 1 such that t[n + 1] is nil. It is similar to the operator #, but may return
-- a different value when there are gaps in the array portion of the table.
-- Intended to be used on data loaded with mw.loadData. For other tables, use #.
-- Note: #frame.args in frame object always be set to 0, regardless of 
-- the number of unnamed template parameters, so use this function for
-- frame.args.
--]]
function p.length(t)
	local i = 1
	while t[i] ~= nil do
		i = i + 1
	end
	return i - 1
end

function p.inArray(arr, valueToFind)
	checkType("inArray", 1, arr, "table")
	
	-- if valueToFind is nil, error?
	
	for _, v in ipairs(arr) do
		if v == valueToFind then
			return true
		end
	end
	
	return false
end

return p