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
Template:ModuleQuality
Loading the module
To use any of the functions, first you must load the module.
localTableTools=require('Module:TableTools')Functions
isPositiveInteger
TableTools.isPositiveInteger(value)
Returnstrue ifvalue is a positive integer, andfalse 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
Returnstrue ifvalue is aNaN value, andfalse 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
TableTools.shallowClone(t)
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 usemw.clone instead.If you want to make a new table with no shared subtables and without metatables transferred, usedeepCopy with thenoMetatable option.
removeDuplicates
TableTools.removeDuplicates(t)
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 firstnil value.(For arrays containingnil values, you can usecompressSparseArray 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
removeDuplicates will return
numKeys
Takes a tablet 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
{'foo',nil,'bar','baz',a='b'},
numKeys will return
.
affixNums
TableTools.affixNums(t,prefix,suffix)
Takes a tablet and returns an array containing the numbers of keys with the optional prefixprefix and the optional suffixsuffix.
For example, for the table
{a1='foo',a3='bar',a6='baz'} and the prefix
'a',
affixNums will return
.
All characters inprefix andsuffix are interpreted literally.
numData
TableTools.numData(t,compress)
Given a table with keys like
"foo1",
"bar1",
"foo2", and
"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 withipairs.
compressSparseArray
TableTools.compressSparseArray(t)
Takes an arrayt with one or more nil values, and removes the nil values while preserving the order, so that the array can be safely traversed withipairs.Any keys that are not positive integers are removed.
For example, for the table
,
compressSparseArray will return
.
sparseIpairs
TableTools.sparseIpairs(t)
This is an iterator function for traversing a sparse arrayt.It is similar toipairs, but will continue to iterate until the highest numerical key, whereasipairs may stop after the firstnil value.Any keys that are not positive integers are ignored.
UsuallysparseIpairs is used in a genericfor loop.
fori,vinTableTools.sparseIpairs(t)do-- code blockend
Note thatsparseIpairs uses thepairs function in its implementation.Although some table keys appear to be ignored, all table keys are accessed when it is run.
size
Finds the size of a key/value pair table.
For example, for the table
,
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 thepairs function to iterate through all of the table keys.
keysToList
TableTools.keysToList(t,keySort)
Returns a list of the keys in a table, sorted using either a default comparison function or a customkeySort function, which follows the same rules as thecomp function supplied toTemplate:Ll.
sortedPairs
TableTools.sortedPairs(t,keySort)
Iterates through a table, with the keys sorted using thekeysToList function.If there are only numerical keys,sparseIpairs is probably more efficient.
isArray
Returns true if all keys in the table are consecutive integers starting at1.
listToSet
TableTools.listToSet(arr)
Creates a set from the array part of the tablearr.Indexing the set by any of the values inarr returnstrue.
localset=TableTools.listToSet{"a","b","c"}assert(set["a"]===true)invert
Transposes the keys and values in an array.For example,invert{ "a", "b", "c" } yields{ a = 1, b = 2, c = 3 }.
deepCopy
TableTools.deepCopy(orig,noMetatable,alreadySeen)
Creates a copy of the tableorig.As withmw.clone, all values that are not functions are duplicated and the identity of tables is preserved.IfnoMetatable istrue, then the metatable (if any) is not copied.Can copy tables loaded withmw.loadData.
Similar tomw.clone, butmw.clone cannot copy tables loaded withmw.loadData and does not allow metatablesnot to be copied.
sparseConcat
TableTools.sparseConcat(t,sep)
Concatenates all values in the table that are indexed by a positive integer, in order.
length
Returns the length of a table, or the first integer keyn counting from0 such thatt[n + 1] isnil.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 withmw.loadData and onframe.args.Both use a metatable such that#mw.loadData("module:...") and#frame.args don't work correctly.For other tables, use#.
inArray
TableTools.inArray(arr,valueToFind)
Returnstrue ifvalueToFind is a member of the arrayarr, andfalse 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. ----------------------------------------------------------------------------------------]]locallibraryUtil=require('libraryUtil')localp={}-- Define often-used variables and functions.localfloor=math.floorlocalinfinity=math.hugelocalcheckType=libraryUtil.checkTypelocalcheckTypeMulti=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.--------------------------------------------------------------------------------------]]functionp.isPositiveInteger(v)iftype(v)=='number'andv>=1andfloor(v)==vandv<infinitythenreturntrueelsereturnfalseendend--[[-------------------------------------------------------------------------------------- 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.--------------------------------------------------------------------------------------]]functionp.isNan(v)iftype(v)=='number'andtostring(v)=='-nan'thenreturntrueelsereturnfalseendend--[[-------------------------------------------------------------------------------------- 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.--------------------------------------------------------------------------------------]]functionp.shallowClone(t)localret={}fork,vinpairs(t)doret[k]=vendreturnretend--[[-------------------------------------------------------------------------------------- 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.--------------------------------------------------------------------------------------]]functionp.removeDuplicates(t)checkType('removeDuplicates',1,t,'table')localisNan=p.isNanlocalret,exists={},{}fori,vinipairs(t)doifisNan(v)then-- NaNs can't be table keys, and they are also unique, so we don't need to check existence.ret[#ret+1]=velseifnotexists[v]thenret[#ret+1]=vexists[v]=trueendendendreturnretend--[[-------------------------------------------------------------------------------------- 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.--------------------------------------------------------------------------------------]]functionp.numKeys(t)checkType('numKeys',1,t,'table')localisPositiveInteger=p.isPositiveIntegerlocalnums={}fork,vinpairs(t)doifisPositiveInteger(k)thennums[#nums+1]=kendendtable.sort(nums)returnnumsend--[[-------------------------------------------------------------------------------------- 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}.--------------------------------------------------------------------------------------]]functionp.affixNums(t,prefix,suffix)checkType('affixNums',1,t,'table')checkType('affixNums',2,prefix,'string',true)checkType('affixNums',3,suffix,'string',true)localfunctioncleanPattern(s)-- Cleans a pattern so that the magic characters ()%.[]*+-?^$ are interpreted literally.s=s:gsub('([%(%)%%%.%[%]%*%+%-%?%^%$])','%%%1')returnsendprefix=prefixor''suffix=suffixor''prefix=cleanPattern(prefix)suffix=cleanPattern(suffix)localpattern='^'..prefix..'([1-9]%d*)'..suffix..'$'localnums={}fork,vinpairs(t)doiftype(k)=='string'thenlocalnum=mw.ustring.match(k,pattern)ifnumthennums[#nums+1]=tonumber(num)endendendtable.sort(nums)returnnumsend--[[-------------------------------------------------------------------------------------- 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.--------------------------------------------------------------------------------------]]functionp.numData(t,compress)checkType('numData',1,t,'table')checkType('numData',2,compress,'boolean',true)localret={}fork,vinpairs(t)dolocalprefix,num=mw.ustring.match(tostring(k),'^([^0-9]*)([1-9][0-9]*)$')ifnumthennum=tonumber(num)localsubtable=ret[num]or{}ifprefix==''then-- Positional parameters match the blank string; put them at the start of the subtable instead.prefix=1endsubtable[prefix]=vret[num]=subtableelselocalsubtable=ret.otheror{}subtable[k]=vret.other=subtableendendifcompressthenlocalother=ret.otherret=p.compressSparseArray(ret)ret.other=otherendreturnretend--[[-------------------------------------------------------------------------------------- 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.--------------------------------------------------------------------------------------]]functionp.compressSparseArray(t)checkType('compressSparseArray',1,t,'table')localret={}localnums=p.numKeys(t)for_,numinipairs(nums)doret[#ret+1]=t[num]endreturnretend--[[-------------------------------------------------------------------------------------- sparseIpairs---- This is an iterator for sparse arrays. It can be used like ipairs, but can-- handle nil values.--------------------------------------------------------------------------------------]]functionp.sparseIpairs(t)checkType('sparseIpairs',1,t,'table')localnums=p.numKeys(t)locali=0locallim=#numsreturnfunction()i=i+1ifi<=limthenlocalkey=nums[i]returnkey,t[key]elsereturnnil,nilendendend--[[-------------------------------------------------------------------------------------- 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.--------------------------------------------------------------------------------------]]functionp.size(t)checkType('size',1,t,'table')locali=0forkinpairs(t)doi=i+1endreturniendlocalfunctiondefaultKeySort(item1,item2)-- "number" < "string", so numbers will be sorted before strings.localtype1,type2=type(item1),type(item2)iftype1~=type2thenreturntype1<type2else-- This will fail with table, boolean, function.returnitem1<item2endend--[[Returns a list of the keys in a table, sorted using either a defaultcomparison function or a custom keySort function.]]functionp.keysToList(t,keySort,checked)ifnotcheckedthencheckType('keysToList',1,t,'table')checkTypeMulti('keysToList',2,keySort,{'function','boolean','nil'})endlocallist={}localindex=1forkey,valueinpairs(t)dolist[index]=keyindex=index+1endifkeySort~=falsethenkeySort=type(keySort)=='function'andkeySortordefaultKeySorttable.sort(list,keySort)endreturnlistend--[[Iterates through a table, with the keys sorted using the keysToList function.If there are only numerical keys, sparseIpairs is probably more efficient.]]functionp.sortedPairs(t,keySort)checkType('sortedPairs',1,t,'table')checkType('sortedPairs',2,keySort,'function',true)locallist=p.keysToList(t,keySort,true)locali=0returnfunction()i=i+1localkey=list[i]ifkey~=nilthenreturnkey,t[key]elsereturnnil,nilendendend--[[Returns true if all keys in the table are consecutive integers starting at 1.--]]functionp.isArray(t)checkType("isArray",1,t,"table")locali=0fork,vinpairs(t)doi=i+1ift[i]==nilthenreturnfalseendendreturntrueend-- { "a", "b", "c" } -> { a = 1, b = 2, c = 3 }functionp.invert(array)checkType("invert",1,array,"table")localmap={}fori,vinipairs(array)domap[v]=iendreturnmapend--[[{ "a", "b", "c" } -> { ["a"] = true, ["b"] = true, ["c"] = true }--]]functionp.listToSet(t)checkType("listToSet",1,t,"table")localset={}for_,iteminipairs(t)doset[item]=trueendreturnsetend--[[Recursive deep copy function.Preserves identities of subtables.]]localfunction_deepCopy(orig,includeMetatable,already_seen)-- Stores copies of tables indexed by the original table.already_seen=already_seenor{}localcopy=already_seen[orig]ifcopy~=nilthenreturncopyendiftype(orig)=='table'thencopy={}fororig_key,orig_valueinpairs(orig)docopy[deepcopy(orig_key,includeMetatable,already_seen)]=deepcopy(orig_value,includeMetatable,already_seen)endalready_seen[orig]=copyifincludeMetatablethenlocalmt=getmetatable(orig)ifmt~=nilthenlocalmt_copy=deepcopy(mt,includeMetatable,already_seen)setmetatable(copy,mt_copy)already_seen[mt]=mt_copyendendelse-- number, string, boolean, etccopy=origendreturncopyendfunctionp.deepCopy(orig,noMetatable,already_seen)checkType("deepCopy",3,already_seen,"table",true)return_deepCopy(orig,notnoMetatable,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"]]functionp.sparseConcat(t,sep,i,j)locallist={}locallist_i=0for_,vinp.sparseIpairs(t)dolist_i=list_i+1list[list_i]=vendreturntable.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.--]]functionp.length(t)locali=1whilet[i]~=nildoi=i+1endreturni-1endfunctionp.inArray(arr,valueToFind)checkType("inArray",1,arr,"table")-- if valueToFind is nil, error?for_,vinipairs(arr)doifv==valueToFindthenreturntrueendendreturnfalseendreturnp
