Module:TableTools: Difference between revisions
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add a fancy introductory comment |
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--[[ |
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------------------------------------------------------------------------------------ |
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-- TableTools -- |
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-- -- |
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⚫ | |||
-- It is a meta-module, meant to be called from other Lua modules, and should -- |
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-- not be called directly from #invoke. -- |
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------------------------------------------------------------------------------------ |
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--]] |
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local p = {} |
local p = {} |
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--[[ |
--[[ |
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----------------------------------------------------------------------------------- |
------------------------------------------------------------------------------------ |
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-- isPositiveInteger |
-- isPositiveInteger |
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-- |
-- |
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-- useful for determining whether a given table key is in the array part or the |
-- useful for determining whether a given table key is in the array part or the |
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-- hash part of a table. |
-- hash part of a table. |
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----------------------------------------------------------------------------------- |
------------------------------------------------------------------------------------ |
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--]] |
--]] |
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function p.isPositiveInteger(num) |
function p.isPositiveInteger(num) |
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--[[ |
--[[ |
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----------------------------------------------------------------------------------- |
------------------------------------------------------------------------------------ |
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-- getNumKeys |
-- getNumKeys |
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-- |
-- |
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-- This takes a table and returns an array containing the numbers of any numerical |
-- This takes a table and returns an array containing the numbers of any numerical |
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-- keys that have non-nil values, sorted in numerical order. |
-- keys that have non-nil values, sorted in numerical order. |
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----------------------------------------------------------------------------------- |
------------------------------------------------------------------------------------ |
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--]] |
--]] |
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function p.getNumKeys(t) |
function p.getNumKeys(t) |
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--[[ |
--[[ |
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----------------------------------------------------------------------------------- |
------------------------------------------------------------------------------------ |
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-- getAffixNums |
-- getAffixNums |
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-- |
-- |
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-- {a1 = 'foo', a3 = 'bar', a6 = 'baz'} and the prefix "a", getAffixNums will |
-- {a1 = 'foo', a3 = 'bar', a6 = 'baz'} and the prefix "a", getAffixNums will |
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-- return {1, 3, 6}. |
-- return {1, 3, 6}. |
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----------------------------------------------------------------------------------- |
------------------------------------------------------------------------------------ |
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--]] |
--]] |
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function p.getAffixNums(t, prefix, suffix) |
function p.getAffixNums(t, prefix, suffix) |
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--[[ |
--[[ |
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----------------------------------------------------------------------------------- |
------------------------------------------------------------------------------------ |
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-- compressSparseArray |
-- compressSparseArray |
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-- |
-- |
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-- while preserving the order, so that the array can be safely traversed with |
-- while preserving the order, so that the array can be safely traversed with |
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-- ipairs. |
-- ipairs. |
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----------------------------------------------------------------------------------- |
------------------------------------------------------------------------------------ |
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--]] |
--]] |
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function p.compressSparseArray(t) |
function p.compressSparseArray(t) |
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--[[ |
--[[ |
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----------------------------------------------------------------------------------- |
------------------------------------------------------------------------------------ |
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-- sparseIpairs |
-- sparseIpairs |
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-- |
-- |
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-- This is an iterator for sparse arrays. It can be used like ipairs, but can |
-- This is an iterator for sparse arrays. It can be used like ipairs, but can |
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-- handle nil values. |
-- handle nil values. |
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----------------------------------------------------------------------------------- |
------------------------------------------------------------------------------------ |
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--]] |
--]] |
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function p.sparseIpairs(t) |
function p.sparseIpairs(t) |
Revision as of 13:10, 15 December 2013
Documentation for this module may be created at Module:TableTools/doc
--[[
------------------------------------------------------------------------------------
-- 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 p = {}
-- Define often-used variables and functions.
local floor = math.floor
local infinity = math.huge
--[[
------------------------------------------------------------------------------------
-- isPositiveInteger
--
-- This function returns true if the given number 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(num)
if type(num) == 'number' and num >= 1 and floor(num) == num and num < infinity then
return true
else
return false
end
end
--[[
------------------------------------------------------------------------------------
-- getNumKeys
--
-- 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.getNumKeys(t)
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
--[[
------------------------------------------------------------------------------------
-- getAffixNums
--
-- 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", getAffixNums will
-- return {1, 3, 6}.
------------------------------------------------------------------------------------
--]]
function p.getAffixNums(t, prefix, suffix)
prefix = prefix or ''
suffix = suffix or ''
local nums = {}
for k, v in pairs(t) do
if type(k) == 'string' then
local num = mw.ustring.match(k, '^' .. prefix .. '([1-9]%d*)' .. suffix .. '$')
if num then
nums[#nums + 1] = tonumber(num)
end
end
end
table.sort(nums)
return nums
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 ret = {}
local nums = p.getNumKeys(t)
table.sort(nums)
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)
local nums = p.getNumKeys(t)
local i = 0
local lim = #nums
return function ()
i = i + 1
if i <= lim then
local key = nums[i]
return key, t[key]
end
end
end
return p