Difference between revisions of "Module:TableTools"
add getNumKeys function and improve the comments, add the beginnings of a sparseIpairs function
>Mr. Stradivarius (start module with useful tools for dealing with Lua tables) |
>Mr. Stradivarius (add getNumKeys function and improve the comments, add the beginnings of a sparseIpairs function) |
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| Line 9: | Line 9: | ||
--[[ | --[[ | ||
----------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------- | ||
-- | -- 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 | if type(num) == 'number' and num >= 1 and floor(num) == num and num < infinity then | ||
return true | return true | ||
| Line 20: | Line 23: | ||
return false | return false | ||
end | 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 | end | ||
| Line 32: | Line 55: | ||
--]] | --]] | ||
function p.compressSparseArray(t) | function p.compressSparseArray(t) | ||
local | local ret = {} | ||
local nums = p.getNumKeys(t) | |||
table.sort(nums) | table.sort(nums) | ||
for _, num in ipairs(nums) do | for _, num in ipairs(nums) do | ||
| Line 44: | Line 63: | ||
return ret | return ret | ||
end | 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 | return p | ||