Module:TableTools: Difference between revisions
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(better error message for the set functions) |
(reinstate shallowClone - saw a use for it in p.complement - and write p.valueComplement) |
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return false |
return false |
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end |
end |
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⚫ | |||
--[[ |
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------------------------------------------------------------------------------------ |
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-- shallowClone |
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-- |
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-- This returns a clone of a table. The value returned is a new table, but all |
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-- subtables and functions are shared. Metamethods are respected, but the returned |
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-- table will have no metatable of its own. |
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------------------------------------------------------------------------------------ |
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--]] |
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function p.shallowClone(t) |
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local ret = {} |
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⚫ | |||
⚫ | |||
end |
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return ret |
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end |
end |
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Line 264: | Line 281: | ||
local tn = select(lim, ...) |
local tn = select(lim, ...) |
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checkType('complement', lim, tn, 'table') |
checkType('complement', lim, tn, 'table') |
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local ret = |
local ret = p.shallowClone(tn) |
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⚫ | |||
⚫ | |||
⚫ | |||
-- Remove all the key/value pairs in t1, t2, ..., tn-1. |
-- Remove all the key/value pairs in t1, t2, ..., tn-1. |
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for i = 1, lim - 1 do |
for i = 1, lim - 1 do |
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Line 276: | Line 290: | ||
ret[k] = nil |
ret[k] = nil |
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end |
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 |
end |
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end |
end |