Module:TableTools: Difference between revisions
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>Mr. Stradivarius (finish sparseIpairs) |
>Mr. Stradivarius (add getAffixNums function) |
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Line 39: | Line 39: | ||
if isPositiveInteger(k) then | if isPositiveInteger(k) then | ||
nums[#nums + 1] = k | 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 | ||
end | end |
Revision as of 07:43, 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 --[[ ----------------------------------------------------------------------------------- -- 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