Difference between revisions of "Module:TableTools"

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--[[
+
-- This module includes a number of functions that can be useful when dealing with Lua tables.
------------------------------------------------------------------------------------
+
--                              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 = {}
 
local p = {}
Line 16: Line 6:
 
local floor = math.floor
 
local floor = math.floor
 
local infinity = math.huge
 
local infinity = math.huge
local checkType = libraryUtil.checkType
 
  
 
--[[
 
--[[
------------------------------------------------------------------------------------
+
-----------------------------------------------------------------------------------
-- isPositiveInteger
+
-- Helper functions
--
+
-----------------------------------------------------------------------------------
-- 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)
 
if type(v) == 'number' and v >= 1 and floor(v) == v and v < infinity then
 
return true
 
else
 
return false
 
end
 
end
 
  
--[[
+
local function isPositiveInteger(num)
------------------------------------------------------------------------------------
+
-- Returns true if the given number is a positive integer, and false if not.
-- isNan
+
if type(num) == 'number' and num >= 1 and floor(num) == num and num < infinity then
--
+
-- 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)
+
if type(v) == 'number' and tostring(v) == '-nan' then
+
 
return true
 
return true
 
else
 
else
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--[[
 
--[[
------------------------------------------------------------------------------------
+
-----------------------------------------------------------------------------------
-- shallowClone
+
-- compressSparseArray
 
--
 
--
-- This returns a clone of a table. The value returned is a new table, but all
+
-- This takes an array with one or more nil values, and removes the nil values
-- subtables and functions are shared. Metamethods are respected, but the returned
+
-- while preserving the order, so that the array can be safely traversed with
-- table will have no metatable of its own.
+
-- ipairs.
------------------------------------------------------------------------------------
+
-----------------------------------------------------------------------------------
 
--]]
 
--]]
function p.shallowClone(t)
+
function p.compressSparseArray(t)
local ret = {}
+
local nums, 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
 
for k, v in pairs(t) do
 
if isPositiveInteger(k) then
 
if isPositiveInteger(k) then
Line 116: Line 39:
 
end
 
end
 
table.sort(nums)
 
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.
 
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 = {}
 
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
 
for _, num in ipairs(nums) do
 
ret[#ret + 1] = t[num]
 
ret[#ret + 1] = t[num]
 
end
 
end
 
return ret
 
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
 
end
  
 
return p
 
return p

Revision as of 12:40, 15 December 2013

Documentation for this module may be created at Module:TableTools/doc

Script error: Lua error: Internal error: The interpreter exited with status 126.

-- This module includes a number of functions that can be useful when dealing with Lua tables.

local p = {}

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

--[[
-----------------------------------------------------------------------------------
-- Helper functions
-----------------------------------------------------------------------------------
--]]

local function isPositiveInteger(num)
	-- Returns true if the given number is a positive integer, and false if not.
	if type(num) == 'number' and num >= 1 and floor(num) == num and num < infinity then
		return true
	else
		return false
	end
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)
	local nums, ret = {}, {}
	for k, v in pairs(t) do
		if isPositiveInteger(k) then
			nums[#nums + 1] = k
		end
	end
	table.sort(nums)
	for _, num in ipairs(nums) do
		ret[#ret + 1] = t[num]
	end
	return ret
end

return p