Module:TableTools: Difference between revisions
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reinstate shallowClone - saw a use for it in p.complement - and write p.valueComplement |
split set functions out to Module:Set |
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Line 96: | Line 96: | ||
end |
end |
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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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-- union |
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-- |
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-- This returns the union of the key/value pairs of n tables. If any of the tables |
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-- contain different values for the same table key, the table value is converted |
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-- to an array holding all of the different values. |
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------------------------------------------------------------------------------------ |
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--]] |
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function p.union(...) |
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local lim = select('#', ...) |
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if lim < 2 then |
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error("too few arguments to 'union' (minimum is 2, received " .. lim .. ')', 2) |
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end |
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local ret, trackArrays = {}, {} |
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for i = 1, lim do |
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local t = select(i, ...) |
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checkType('union', i, t, 'table') |
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for k, v in pairs(t) do |
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local retKey = ret[k] |
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if retKey == nil then |
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ret[k] = v |
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elseif retKey ~= v then |
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if trackArrays[k] then |
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local array = ret[k] |
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local valExists |
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for _, arrayVal in ipairs(array) do |
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if arrayVal == v then |
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valExists = true |
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break |
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end |
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end |
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if not valExists then |
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array[#array + 1] = v |
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ret[k] = array |
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end |
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else |
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ret[k] = {ret[k], v} |
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trackArrays[k] = true |
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end |
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end |
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end |
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end |
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return ret |
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end |
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--[[ |
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------------------------------------------------------------------------------------ |
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-- valueUnion |
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-- |
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-- This returns the union of the values of n tables, as an array. For example, for |
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-- the tables {1, 3, 4, 5, foo = 7} and {2, bar = 3, 5, 6}, union will return |
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-- {1, 2, 3, 4, 5, 6, 7}. |
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------------------------------------------------------------------------------------ |
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--]] |
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function p.valueUnion(...) |
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local lim = select('#', ...) |
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if lim < 2 then |
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error("too few arguments to 'valueUnion' (minimum is 2, received " .. lim .. ')', 2) |
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end |
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local isNan = p.isNan |
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local ret, exists = {}, {} |
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for i = 1, lim do |
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local t = select(i, ...) |
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checkType('valueUnion', i, t, 'table') |
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for k, v in pairs(t) do |
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if isNan(v) then |
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ret[#ret + 1] = v |
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elseif not exists[v] then |
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ret[#ret + 1] = v |
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exists[v] = true |
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end |
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end |
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end |
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return ret |
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end |
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--[[ |
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------------------------------------------------------------------------------------ |
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-- intersection |
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-- |
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-- This returns the intersection of the key/value pairs of n tables. Both the key |
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-- and the value must match to be included in the resulting table. |
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------------------------------------------------------------------------------------ |
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--]] |
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function p.intersection(...) |
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local lim = select('#', ...) |
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if lim < 2 then |
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error("too few arguments to 'intersection' (minimum is 2, received " .. lim .. ')', 2) |
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end |
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local ret, track, pairCounts = {}, {}, {} |
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for i = 1, lim do |
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local t = select(i, ...) |
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checkType('intersection', i, t, 'table') |
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for k, v in pairs(t) do |
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local trackVal = track[k] |
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if trackVal == nil then |
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track[k] = v |
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pairCounts[k] = 1 |
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elseif trackVal == v then |
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pairCounts[k] = pairCounts[k] + 1 |
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end |
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end |
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end |
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for k, v in pairs(track) do |
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if pairCounts[k] == lim then |
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ret[k] = v |
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end |
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end |
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return ret |
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end |
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--[[ |
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------------------------------------------------------------------------------------ |
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-- valueIntersection |
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-- |
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-- This returns the intersection of the values of n tables, as an array. For |
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-- example, for the tables {1, 3, 4, 5, foo = 7} and {2, bar = 3, 5, 6}, |
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-- intersection will return {3, 5}. |
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------------------------------------------------------------------------------------ |
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--]] |
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function p.valueIntersection(...) |
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local lim = select('#', ...) |
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if lim < 2 then |
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error("too few arguments to 'valueIntersection' (minimum is 2, received " .. lim .. ')', 2) |
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end |
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local isNan = p.isNan |
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local vals, ret = {}, {} |
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local isSameTable = true -- Tracks table equality. |
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local tableTemp -- Used to store the table from the previous loop so that we can check table equality. |
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for i = 1, lim do |
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local t = select(i, ...) |
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checkType('valueIntersection', i, t, 'table') |
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if tableTemp and t ~= tableTemp then |
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isSameTable = false |
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end |
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tableTemp = t |
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for k, v in pairs(t) do |
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-- NaNs are never equal to any other value, so they can't be in the intersection. |
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-- Which is lucky, as they also can't be table keys. |
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if not isNan(v) then |
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local valCount = vals[v] or 0 |
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vals[v] = valCount + 1 |
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end |
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end |
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end |
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if isSameTable then |
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-- If all the tables are equal, then the intersection is that table (including NaNs). |
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-- All we need to do is convert it to an array and remove duplicate values. |
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for k, v in pairs(tableTemp) do |
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ret[#ret + 1] = v |
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end |
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return p.removeDuplicates(ret) |
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end |
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for val, count in pairs(vals) do |
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if count == lim then |
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ret[#ret + 1] = val |
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end |
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end |
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return ret |
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end |
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--[[ |
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------------------------------------------------------------------------------------ |
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-- complement |
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-- |
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-- This returns the relative complement of t1, t2, ..., in tn. The complement |
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-- is of key/value pairs. This is equivalent to all the key/value pairs that are in |
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-- tn but are not in t1, t2, ... tn-1. |
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------------------------------------------------------------------------------------ |
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--]] |
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function p.complement(...) |
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local lim = select('#', ...) |
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if lim < 2 then |
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error("too few arguments to 'complement' (minimum is 2, received " .. lim .. ')', 2) |
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end |
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--[[ |
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-- Now we know that we have at least two sets. |
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-- First, get all the key/value pairs in tn. We can't simply make ret equal to tn, |
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-- as that will affect the value of tn for the whole module. |
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--]] |
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local tn = select(lim, ...) |
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checkType('complement', lim, tn, 'table') |
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local ret = p.shallowClone(tn) |
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-- Remove all the key/value pairs in t1, t2, ..., tn-1. |
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for i = 1, lim - 1 do |
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local t = select(i, ...) |
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checkType('complement', i, t, 'table') |
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for k, v in pairs(t) do |
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if ret[k] == v then |
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ret[k] = nil |
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end |
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end |
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end |
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return ret |
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end |
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--[[ |
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------------------------------------------------------------------------------------ |
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-- valueComplement |
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-- |
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-- This returns an array containing the relative complement of t1, t2, ..., in tn. |
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-- The complement is of values only. This is equivalent to all the values that are |
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-- in tn but are not in t1, t2, ... tn-1. |
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------------------------------------------------------------------------------------ |
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--]] |
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function p.valueComplement(...) |
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local lim = select('#', ...) |
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if lim < 2 then |
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error("too few arguments to 'valueComplement' (minimum is 2, received " .. lim .. ')', 2) |
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end |
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local isNan = p.isNan |
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local ret, exists = {}, {} |
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for i = 1, lim - 1 do |
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local t = select(i, ...) |
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checkType('valueComplement', i, t, 'table') |
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for k, v in pairs(t) do |
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if not isNan(v) then |
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-- NaNs cannot be table keys, and they are also unique so cannot be equal to anything in tn. |
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exists[v] = true |
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end |
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end |
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end |
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local tn = select(lim, ...) |
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checkType('valueComplement', lim, tn, 'table') |
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for k, v in pairs(tn) do |
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if isNan(v) or exists[v] == nil then |
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ret[#ret + 1] = v |
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end |
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end |
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return ret |
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end |
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--[[ |
--[[ |
Revision as of 05:46, 20 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 libraryUtil = require('libraryUtil')
local p = {}
-- Define often-used variables and functions.
local floor = math.floor
local infinity = math.huge
local checkType = libraryUtil.checkType
--[[
------------------------------------------------------------------------------------
-- isPositiveInteger
--
-- This function returns true if the given value 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(v)
if type(v) == 'number' and v >= 1 and floor(v) == v and v < infinity then
return true
else
return false
end
end
--[[
------------------------------------------------------------------------------------
-- isNan
--
-- This function returns true if the given number is a NaN value, and false
-- if not. Although it doesn't operate on tables, it is included here as it is
-- useful for determining whether a value can be a valid table key. Lua will
-- generate an error if a NaN is used as a table key.
------------------------------------------------------------------------------------
--]]
function p.isNan(v)
if type(v) == 'number' and tostring(v) == '-nan' then
return true
else
return false
end
end
--[[
------------------------------------------------------------------------------------
-- shallowClone
--
-- This returns a clone of a table. The value returned is a new table, but all
-- subtables and functions are shared. Metamethods are respected, but the returned
-- table will have no metatable of its own.
------------------------------------------------------------------------------------
--]]
function p.shallowClone(t)
local ret = {}
for k, v in pairs(t) do
ret[k] = v
end
return ret
end
--[[
------------------------------------------------------------------------------------
-- removeDuplicates
--
-- This removes duplicate values from an array. Non-positive-integer keys are
-- ignored. The earliest value is kept, and all subsequent duplicate values are
-- removed, but otherwise the array order is unchanged.
------------------------------------------------------------------------------------
--]]
function p.removeDuplicates(t)
checkType('removeDuplicates', 1, t, 'table')
local isNan = p.isNan
local ret, exists = {}, {}
for i, v in ipairs(t) do
if isNan(v) then
-- NaNs can't be table keys, and they are also unique, so we don't need to check existence.
ret[#ret + 1] = v
else
if not exists[v] then
ret[#ret + 1] = v
exists[v] = true
end
end
end
return ret
end
--[[
------------------------------------------------------------------------------------
-- numKeys
--
-- 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.numKeys(t)
checkType('numKeys', 1, t, 'table')
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
--[[
------------------------------------------------------------------------------------
-- affixNums
--
-- 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", affixNums will
-- return {1, 3, 6}.
------------------------------------------------------------------------------------
--]]
function p.affixNums(t, prefix, suffix)
checkType('affixNums', 1, t, 'table')
checkType('affixNums', 2, prefix, 'string', true)
checkType('affixNums', 3, suffix, 'string', true)
prefix = prefix or ''
suffix = suffix or ''
local pattern = '^' .. prefix .. '([1-9]%d*)' .. suffix .. '$'
local nums = {}
for k, v in pairs(t) do
if type(k) == 'string' then
local num = mw.ustring.match(k, pattern)
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)
checkType('compressSparseArray', 1, t, 'table')
local ret = {}
local nums = p.numKeys(t)
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)
checkType('sparseIpairs', 1, t, 'table')
local nums = p.numKeys(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
--[[
------------------------------------------------------------------------------------
-- size
--
-- This returns the size of a key/value pair table. It will also work on arrays,
-- but for arrays it is more efficient to use the # operator.
------------------------------------------------------------------------------------
--]]
function p.size(t)
checkType('size', 1, t, 'table')
local i = 0
for k in pairs(t) do
i = i + 1
end
return i
end
return p