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Module:TableTools: Difference between revisions
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add getNumKeys function and improve the comments, add the beginnings of a sparseIpairs function
(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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Line 9:
--[[
-----------------------------------------------------------------------------------
--
-- 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)
▲local function isPositiveInteger(num)
▲ -- Returns true if the given number is a positive integer, and false if not.
if type(num) == 'number' and num >= 1 and floor(num) == num and num < infinity then
return true
Line 24 ⟶ 27:
--[[
-----------------------------------------------------------------------------------
-- getNumKeys
-- compressSparseArray▼
--
-- This takes
-- keys that have non-nil values, sorted in numerical order.
-- while preserving the order, so that the array can be safely traversed with▼
-- ipairs.▼
-----------------------------------------------------------------------------------
--]]
function p.
local
local nums = {}
for k, v in pairs(t) do
if isPositiveInteger(k) then
Line 38 ⟶ 41:
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
Line 44 ⟶ 63:
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
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