Module:TableTools: Difference between revisions
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start module with useful tools for dealing with Lua tables |
add getNumKeys function and improve the comments, add the beginnings of a sparseIpairs function |
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--[[ |
--[[ |
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----------------------------------------------------------------------------------- |
----------------------------------------------------------------------------------- |
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-- Helper functions |
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-- |
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-- if not. Although it doesn't operate on tables, it is included here as it is |
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-- useful for determining whether a given table key is in the array part or the |
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-- hash part of the table. |
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----------------------------------------------------------------------------------- |
----------------------------------------------------------------------------------- |
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--]] |
--]] |
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function p.isPositiveInteger(num) |
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if type(num) == 'number' and num >= 1 and floor(num) == num and num < infinity then |
if type(num) == 'number' and num >= 1 and floor(num) == num and num < infinity then |
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return true |
return true |
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--[[ |
--[[ |
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----------------------------------------------------------------------------------- |
----------------------------------------------------------------------------------- |
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-- getNumKeys |
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-- |
-- |
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-- This takes |
-- 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. |
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----------------------------------------------------------------------------------- |
----------------------------------------------------------------------------------- |
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--]] |
--]] |
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function p. |
function p.getNumKeys(t) |
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local |
local isPositiveInteger = p.isPositiveInteger |
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local nums = {} |
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for k, v in pairs(t) do |
for k, v in pairs(t) do |
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if isPositiveInteger(k) then |
if isPositiveInteger(k) then |
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end |
end |
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end |
end |
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table.sort(nums) |
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return nums |
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end |
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--[[ |
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----------------------------------------------------------------------------------- |
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-- |
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-- This takes an array with one or more nil values, and removes the nil values |
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----------------------------------------------------------------------------------- |
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--]] |
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function p.compressSparseArray(t) |
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local ret = {} |
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local nums = p.getNumKeys(t) |
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table.sort(nums) |
table.sort(nums) |
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for _, num in ipairs(nums) do |
for _, num in ipairs(nums) do |
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return ret |
return ret |
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end |
end |
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--[[ |
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----------------------------------------------------------------------------------- |
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-- sparseIpairs |
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-- |
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-- This is an iterator for sparse arrays. It can be used like ipairs, but can |
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-- handle nil values. |
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----------------------------------------------------------------------------------- |
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--]] |
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-- function p.sparseIpairs(t) |
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-- local nums = p.getNumKeys(t) |
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return p |
return p |
Revision as of 11:33, 15 December 2013
Documentation for this module may be created at Module:TableTools/doc
-- 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
--[[
-----------------------------------------------------------------------------------
-- 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 the 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
--[[
-----------------------------------------------------------------------------------
-- 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)
return p