Module:TableTools
--[[
-- 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)
return type(v) == 'number' and v >= 1 and floor(v) == v and v < infinity
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)
return type(v) == 'number' and tostring(v) == '-nan'
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.
return s:gsub('([%(%)%%%.%[%]%*%+%-%?%^%$])', '%%%1')
end
prefix = prefix or
suffix = suffix or
prefix = cleanPattern(prefix)
suffix = cleanPattern(suffix)
local pattern = '^' .. prefix .. '([1-9]%d*)' .. suffix .. '$'
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 --[[ -- Finds the length of an array, or of a quasi-array with keys such -- as "data1", "data2", etc., using an exponential search algorithm. -- 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, prefix)
-- requiring module inline so that Module:Exponential search -- which is only needed by this one function -- doesn't get millions of transclusions local expSearch = require("Module:Exponential search") 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 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
