Difference between revisions of "TableTools"
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| − | -- This module includes a number of functions | + | --[[ |
| + | ------------------------------------------------------------------------------------ | ||
| + | -- 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 = {} | local p = {} | ||
| Line 8: | Line 16: | ||
--[[ | --[[ | ||
| − | ----------------------------------------------------------------------------------- | + | ------------------------------------------------------------------------------------ |
-- isPositiveInteger | -- isPositiveInteger | ||
-- | -- | ||
| Line 15: | Line 23: | ||
-- 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 | ||
-- hash part of a table. | -- hash part of a table. | ||
| − | ----------------------------------------------------------------------------------- | + | ------------------------------------------------------------------------------------ |
--]] | --]] | ||
function p.isPositiveInteger(num) | function p.isPositiveInteger(num) | ||
| Line 26: | Line 34: | ||
--[[ | --[[ | ||
| − | ----------------------------------------------------------------------------------- | + | ------------------------------------------------------------------------------------ |
-- getNumKeys | -- getNumKeys | ||
-- | -- | ||
-- 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 | ||
-- keys that have non-nil values, sorted in numerical order. | -- keys that have non-nil values, sorted in numerical order. | ||
| − | ----------------------------------------------------------------------------------- | + | ------------------------------------------------------------------------------------ |
--]] | --]] | ||
function p.getNumKeys(t) | function p.getNumKeys(t) | ||
| Line 46: | Line 54: | ||
--[[ | --[[ | ||
| − | ----------------------------------------------------------------------------------- | + | ------------------------------------------------------------------------------------ |
-- getAffixNums | -- getAffixNums | ||
-- | -- | ||
| Line 53: | Line 61: | ||
-- {a1 = 'foo', a3 = 'bar', a6 = 'baz'} and the prefix "a", getAffixNums will | -- {a1 = 'foo', a3 = 'bar', a6 = 'baz'} and the prefix "a", getAffixNums will | ||
-- return {1, 3, 6}. | -- return {1, 3, 6}. | ||
| − | ----------------------------------------------------------------------------------- | + | ------------------------------------------------------------------------------------ |
--]] | --]] | ||
function p.getAffixNums(t, prefix, suffix) | function p.getAffixNums(t, prefix, suffix) | ||
| Line 72: | Line 80: | ||
--[[ | --[[ | ||
| − | ----------------------------------------------------------------------------------- | + | ------------------------------------------------------------------------------------ |
-- compressSparseArray | -- compressSparseArray | ||
-- | -- | ||
| Line 78: | Line 86: | ||
-- 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 | ||
-- ipairs. | -- ipairs. | ||
| − | ----------------------------------------------------------------------------------- | + | ------------------------------------------------------------------------------------ |
--]] | --]] | ||
function p.compressSparseArray(t) | function p.compressSparseArray(t) | ||
| Line 91: | Line 99: | ||
--[[ | --[[ | ||
| − | ----------------------------------------------------------------------------------- | + | ------------------------------------------------------------------------------------ |
-- sparseIpairs | -- sparseIpairs | ||
-- | -- | ||
-- 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 | ||
-- handle nil values. | -- handle nil values. | ||
| − | ----------------------------------------------------------------------------------- | + | ------------------------------------------------------------------------------------ |
--]] | --]] | ||
function p.sparseIpairs(t) | function p.sparseIpairs(t) | ||
Revision as of 07:10, 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