Module:table
Dokumentasie vir hierdie module kan geskep word by: Module:table/doc
--[[
------------------------------------------------------------------------------------
-- table (formerly TableTools) --
-- --
-- This module inclcudes 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)
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 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)
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, checked)
if not checked then
checkType('numKeys', 1, t, 'table')
end
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
function export.maxIndex(t)
checkType('maxIndex', 1, t, 'table')
local positiveIntegerKeys = export.numKeys(t)
if positiveIntegerKeys[1] then
return math.max(unpack(positiveIntegerKeys))
else
return 0 -- ???
end
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
--[[
Recursively compare two values that may be tables, including tables with
nested tables as values. Return true if both values are structurally equal.
Note that this handles arbitary levels of nesting. If all tables are known
to be lists (with only integral keys), use export.deepEqualsList, which will
be more efficient.
NOTE: This is *NOT* smart enough to properly handle cycles; in such a case, it
will get into an infinite loop.
]]
function export.deepEquals(x, y)
if type(x) == "table" and type(y) == "table" then
-- Two tables are the same if they have the same number of elements
-- and all keys that are present in one of the tables compare equal
-- to the corresponding keys in the other table, using structural
-- comparison.
local sizex = 0
for key, value in pairs(x) do
if not export.deepEquals(value, y[key]) then
return false
end
sizex = sizex + 1
end
local sizey = export.size(y)
if sizex ~= sizey then
return false
end
return true
end
return x == y
end
--[[
Recursively compare two values that may be lists (i.e. tables with integral
keys), including lists with nested lists as values. Return true if both values
are structurally equal. Note that this handles arbitary levels of nesting.
Results are undefined if tables with non-integral keys are present anywhere in
either structure; if that may be the case, use export.deepEquals, which will
handle such tables correctly but be less efficient on lists than
export.deepEqualsList.
NOTE: This is *NOT* smart enough to properly handle cycles; in such a case, it
will get into an infinite loop.
]]
function export.deepEqualsList(x, y)
if type(x) == "table" and type(y) == "table" then
if #x ~= #y then
return false
end
for key, value in ipairs(x) do
if not export.deepEqualsList(value, y[key]) then
return false
end
end
return true
end
return x == y
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 conjunction, normally "and".
An improvement on mw.text.listToText, which doesn't properly handle serial
commas.
Options:
- conj
Conjunction to use; defaults to "and".
- 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 = options.conj or "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 '<span class="serial-comma">,</span>'
conj = options.dontTag and ' ' .. conj .. " " or '<span class="serial-and"> ' .. conj .. '</span> '
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