模組:TableTools
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本模块包含一系列用于处理Lua表的函数。这是个元模块,用于其他Lua模块调用,而不应该由#invoke直接调用。
加载模块
如需加载任何函数,首先需要加载模块。
local TableTools = require('Module:TableTools')
isPositiveInteger
TableTools.isPositiveInteger(value)
如果value
是正整数,返回true
,否则返回false
。虽然此函数不是应用于表的,但这里仍收录了此函数以决定一个给定的键是否在表的数组部分或哈希部分。
isNan
TableTools.isNan(value)
如果value
是NaN值,返回true
,否则返回false
。虽然此函数不是应用于表的,但这里仍收录了此函数以决定一个值能否作为有效的键。(将NaN作为键会报错。)
shallowClone
TableTools.shallowClone(t)
返回表格的副本。返回的值是一个新表,但是所有的子表和函数都会共用。不会绕过元表,但返回的表自身不会带有元表。如需在创建新表时不共享子表格且要复制元表,可以使用mw.clone。
removeDuplicates
TableTools.removeDuplicates(t)
从数组中返回重复值。此函数仅用于标准的数组,所有非正整数键的一律忽略,第一个nil
后的值也会忽略。(对于包含nil
的数组,可以先使用compressSparseArray。)此函数尝试保护数组的顺序:有重复值时,仅保留最早出现的那个。例如,对于表{5, 4, 4, 3, 4, 2, 2, 1}
,removeDuplicates返回{5, 4, 3, 2, 1}
。
numKeys
TableTools.numKeys(t)
接收表t
并以数字顺序返回拥有非nil值的正整数键的数量。例如,对于{'foo', nil, 'bar', 'baz', a = 'b'}
,numKeys返回{1, 3, 4}
。
affixNums
TableTools.affixNums(t, prefix, suffix)
接收表t
并返回包含含有可选前缀prefix
和可选后缀suffix
的键的数量的数组。例如,对于表{a1 = 'foo', a3 = 'bar', a6 = 'baz'}
和前缀'a'
,affixNums返回{1, 3, 6}
。prefix
和suffix
的值均按字面解释(不使用正则表达式)。
numData
TableTools.numData(t, compress)
假如一个表有像foo1、bar1、foo2、baz2这样的键,返回如下格式的子表的表{ [1] = {foo = 'text', bar = 'text'}, [2] = {foo = 'text', baz = 'text'} }
。不以整数结尾的键存储在命名为other的子表中。compress选项会压缩表以便通过ipairs迭代。
compressSparseArray
TableTools.compressSparseArray(t)
接收一个带有一个或更多nil值的数组t
,移除所有的nil值,不影响其他值的顺序,以便于安全地通过ipairs遍历。所有非正整数的键都会移除。例如,对于表{1, nil, foo = 'bar', 3, 2}
,compressSparseArray返回{1, 3, 2}
。
sparseIpairs
TableTools.sparseIpairs(t)
这是用于遍历稀疏数组t
的迭代器函数。类似于ipairs,但会一直迭代直到最高的数字键,而ipairs遇到第一个nil
就可能会终止。忽略所有的非正整数键。
sparseIpairs常用于通用的for
循环。
for i, v in TableTools.sparseIpairs(t) do
-- 代码
end
注意sparseIpairs会在实现时使用pairs。尽管一些键看上去被忽略,但实际上运行时也会遍历到。
size
TableTools.size(t)
寻找“键/值对”表的大小。例如,对于{foo = 'foo', bar = 'bar'}
,size返回2
。函数也可以用于数组,但是对于数组,使用#操作符更高效。注意,为了查找表的大小,函数会使用pairs函数以遍历所有的表键。
keysToList
TableTools.keysToList(t, keySort)
返回表的键的列表,并按默认比较函数或者自定义keySort
函数排序,与table.sort
的comp
函数类似。
sortedPairs
TableTools.sortedPairs(t, keySort)
迭代表,并使用keysToList
函数来排序键。如果只有数字键,sparseIpairs
可能更高效。
isArray
TableTools.isArray(t)
如果表中的所有键都是以1
开始的接连不断的整数,返回true。
listToSet
TableTools.listToSet(arr)
从表arr
的数组部分创建一个集(set)。用arr
的任何值来索引集都会返回true
。
local set = TableTools.listToSet { "a", "b", "c" }
assert(set["a"] == true)
invert
TableTools.invert(t)
交换数组中的键和值。例如,invert{ "a", "b", "c" }
产生{ a = 1, b = 2, c = 3 }
。
deepCopy
TableTools.deepCopy(orig, noMetatable, alreadySeen)
返回表orig
的副本,类似于mw.clone
,所有非函数的值都会复制,并保留表的唯一性。如果noMetatable
为true
,则不会复制元表(如有)。可以复制由mw.loadData
加载的表。
与mw.clone
类似,但mw.clone
不能够复制由mw.loadData
加载的表,也不允许拒绝复制元表。
sparseConcat
TableTools.sparseConcat(t, sep)
按顺序连接被正整数索引的表的所有值。
length
TableTools.length(t)
查找数组的长度,或者带有像data1、data2这样的键的准数组。使用指数搜索算法以查找长度,以便于尽可能少地使用表查找(table lookup)。
对于准数组,此算法对使用元表的数组有用(例如frame.args)。对于正常数组,只需要使用#操作符,因为#操作符是由C语言实现的,速度更快。
inArray
TableTools.inArray(arr, valueToFind)
如果valueToFind
是数组arr
的成员,返回true
,否则返回false
。
上述文档嵌入自Module:TableTools/doc。 (编辑 | 历史) 编者可以在本模块的沙盒 (编辑 | 差异)和测试样例 (创建)页面进行实验。 本模块的子页面。 |
------------------------------------------------------------------------------------
-- 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 v ~= v
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)
checkType('shallowClone', 1, t, 'table')
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(arr)
checkType('removeDuplicates', 1, arr, 'table')
local isNan = p.isNan
local ret, exists = {}, {}
for _, v in ipairs(arr) 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 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 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 _ 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
elseif type1 == 'table' or type1 == 'boolean' or type1 == 'function' then
return tostring(item1) < tostring(item2)
else
return item1 < item2
end
end
------------------------------------------------------------------------------------
-- keysToList
--
-- Returns an array 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 arr = {}
local index = 1
for k in pairs(t) do
arr[index] = k
index = index + 1
end
if keySort ~= false then
keySort = type(keySort) == 'function' and keySort or defaultKeySort
table.sort(arr, keySort)
end
return arr
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.
------------------------------------------------------------------------------------
function p.sortedPairs(t, keySort)
checkType('sortedPairs', 1, t, 'table')
checkType('sortedPairs', 2, keySort, 'function', true)
local arr = p.keysToList(t, keySort, true)
local i = 0
return function ()
i = i + 1
local key = arr[i]
if key ~= nil then
return key, t[key]
else
return nil, nil
end
end
end
------------------------------------------------------------------------------------
-- isArray
--
-- Returns true if the given value is a table and all keys are consecutive
-- integers starting at 1.
------------------------------------------------------------------------------------
function p.isArray(v)
if type(v) ~= 'table' then
return false
end
local i = 0
for _ in pairs(v) 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
if v[i] == nil then
return false
end
end
return true
end
------------------------------------------------------------------------------------
-- invert
--
-- 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 = {}
for i, v in ipairs(arr) do
if not isNan(v) then
map[v] = i
end
end
return map
end
------------------------------------------------------------------------------------
-- listToSet
--
-- Creates a set from the array part of the table. Indexing the set by any of the
-- values of the array returns true. For example, {"a", "b", "c"} ->
-- {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 = {}
for _, v in ipairs(arr) do
if not isNan(v) then
set[v] = true
end
end
return set
end
------------------------------------------------------------------------------------
-- deepCopy
--
-- 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
------------------------------------------------------------------------------------
-- sparseConcat
--
-- 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 arr = {}
local arr_i = 0
for _, v in p.sparseIpairs(t) do
arr_i = arr_i + 1
arr[arr_i] = v
end
return table.concat(arr, sep, i, j)
end
------------------------------------------------------------------------------------
-- length
--
-- 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
------------------------------------------------------------------------------------
-- inArray
--
-- Returns true if valueToFind is a member of the array, and false otherwise.
------------------------------------------------------------------------------------
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