Module:Table

--[[

---

-- table (formerly 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. --

---

--]]

--[[ Inserting new values into a table using a local "index" variable, which is incremented each time, is faster than using "table.insert(t, x)" or "t[#t + 1] = x". See the talk page. ]]

local libraryUtil = require('libraryUtil')

local export = {}

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

local function _check(funcName, expectType) if type(expectType) == "string" then return function(argIndex, arg, nilOk) checkType(funcName, argIndex, arg, expectType, nilOk) end else return function(argIndex, arg, expectType, nilOk) if type(expectType) == "table" then checkTypeMulti(funcName, argIndex, arg, expectType, nilOk) else checkType(funcName, argIndex, arg, expectType, nilOk) end end end end

--[[

---

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

--[[ Shallow copy ]] function export.shallowcopy(orig) local orig_type = type(orig) local copy if orig_type == 'table' then copy = {} for orig_key, orig_value in pairs(orig) do copy[orig_key] = orig_value end else -- number, string, boolean, etc copy = orig end return copy end

--[[ Recursive deep copy function Equivalent to mw.clone? ]] 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 export.deepcopy(orig, noMetatable, already_seen) checkType("deepcopy", 3, already_seen, "table", true)

return deepcopy(orig, not noMetatable, already_seen) 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 export.removeDuplicates(t) checkType('removeDuplicates', 1, t, 'table') local isNan = export.isNan local ret, exists = {}, {} local index = 1 for _, 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[index] = v index = index + 1 else if not exists[v] then ret[index] = v index = index + 1 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 export.numKeys(t) checkType('numKeys', 1, t, 'table') local isPositiveInteger = export.isPositiveInteger local nums = {} local index = 1 for k, _ in pairs(t) do if isPositiveInteger(k) then nums[index] = k index = index + 1 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. -- affixNums({a1 = 'foo', a3 = 'bar', a6 = 'baz'}, "a") -- ↓ -- {1, 3, 6}.

---

--]] function export.affixNums(t, prefix, suffix) local check = _check('affixNums') check(1, t, 'table') check(2, prefix, 'string', true) check(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 = {} local index = 1 for k, _ in pairs(t) do if type(k) == 'string' then local num = mw.ustring.match(k, pattern) if num then nums[index] = tonumber(num) index = index + 1 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 export.numData(t, compress) local check = _check('numData') check(1, t, 'table') check(2, compress, 'boolean', true)

local ret = {} for k, v in pairs(t) do local prefix, num = tostring(k):match('^([^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 = export.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 export.compressSparseArray(t) checkType('compressSparseArray', 1, t, 'table') local ret = {} local index = 1 local nums = export.numKeys(t) for _, num in ipairs(nums) do ret[index] = t[num] index = index + 1 end return ret end

--[[

---

-- sparseIpairs -- -- This is an iterator for sparse arrays. It can be used like ipairs, but can -- handle nil values.

---

--]] function export.sparseIpairs(t) checkType('sparseIpairs', 1, t, 'table') local nums = export.numKeys(t) local i = 0 return function() i = i + 1 local key = nums[i] if key then 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 export.size(t) checkType('size', 1, t, 'table') local i = 0 for _ in pairs(t) do i = i + 1 end return i 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 #. --]] function export.length(t) local i = 0 repeat i = i + 1 until t[i] == nil return i - 1 end

--[[ Takes table and a value to be found. If the value is in the array portion of the table, return true. If the value is in the hashmap or not in the table, return false. ]] function export.contains(list, x) for _, v in ipairs(list) do if v == x then return true end end return false end

--[[ Finds key for specified value in a given table. Roughly equivalent to reversing the key-value pairs in the table – reversed_table = { [value1] = key1, [value2] = key2, ... } – and then returning reversed_table[valueToFind].

The value can only be a string or a number (not nil, a boolean, a table, or a function).

Only reliable if there is just one key with the specified value. Otherwise, the function returns the first key found, and the output is unpredictable. ]] function export.keyFor(t, valueToFind) local check = _check('keyFor') check(1, t, 'table') check(2, valueToFind, { 'string', 'number' })

for key, value in pairs(t) do if value == valueToFind then return key end end

return nil end

--[[ The default sorting function used in export.keysToList if no keySort is defined. ]] local function defaultKeySort(key1, key2) -- "number" < "string", so numbers will be sorted before strings. local type1, type2 = type(key1), type(key2) if type1 ~= type2 then return type1 < type2 else return key1 < key2 end end

--[[ Returns a list of the keys in a table, sorted using either the default table.sort function or a custom keySort function. If there are only numerical keys, numKeys is probably more efficient. ]] function export.keysToList(t, keySort, checked) if not checked then local check = _check('keysToList') check(1, t, 'table') check(2, keySort, 'function', true) end

local list = {} local index = 1 for key, _ in pairs(t) do list[index] = key index = index + 1 end

-- Place numbers before strings, otherwise sort using <. if not keySort then keySort = defaultKeySort end

table.sort(list, keySort)

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 export.sortedPairs(t, keySort) local check = _check('keysToList') check(1, t, 'table') check(2, keySort, 'function', true)

local list = export.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

function export.reverseIpairs(list) checkType('reverse_ipairs', 1, list, 'table')

local i = #list + 1 return function() i = i - 1 if list[i] ~= nil then return i, list[i] else return nil, nil end end end

--[=[ Joins an array with serial comma and serial "and". An improvement on mw.text.listToText, which doesn't properly handle serial commas.

Options: - italicizeConj Italicize conjunction: for Module:Template:also - dontTag Don't tag the serial comma and serial "and". For error messages, in which HTML cannot be used. ]=] function export.serialCommaJoin(seq, options) local check = _check("serialCommaJoin", "table") check(1, seq) check(2, options, true)

local length = #seq

if not options then options = {} end

local conj if length > 1 then conj = "and" if options.italicizeConj then conj = "" .. conj .. "" end end

if length == 0 then return "" elseif length == 1 then return seq[1] -- nothing to join elseif length == 2 then return seq[1] .. " " .. conj .. " " .. seq[2] else local comma = options.dontTag and "," or ',' conj = options.dontTag and ' ' .. conj .. " " or ' ' .. conj .. ' ' return table.concat(seq, ", ", 1, length - 1) .. comma .. conj .. seq[length] end 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 export.sparseConcat(t, sep, i, j) local list = {}

local list_i = 0 for _, v in export.sparseIpairs(t) do list_i = list_i + 1 list[list_i] = v end

return table.concat(list, sep, i, j) end

--[[ Values of numberic keys in array portion of table are reversed: { "a", "b", "c" } -> { "c", "b", "a" } --]] function export.reverse(t) checkType("reverse", 1, t, "table")

local new_t = {} local new_t_i = 1 for i = #t, 1, -1 do new_t[new_t_i] = t[i] new_t_i = new_t_i + 1 end return new_t end

function export.reverseConcat(t, sep, i, j) return table.concat(export.reverse(t), sep, i, j) end

-- { "a", "b", "c" } -> { a = 1, b = 2, c = 3 } function export.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 export.listToSet(t) checkType("listToSet", 1, t, "table")

local set = {} for _, item in ipairs(t) do set[item] = true end return set end

--[[ Returns true if all keys in the table are consecutive integers starting at 1. --]] function export.isArray(t) checkType("isArray", 1, t, "table")

local i = 0 for _ in pairs(t) do i = i + 1 if t[i] == nil then return false end end return true end

return export