Module:TableTools: Difference between revisions
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(generate an error message when union and intersection functions are called with no arguments) |
(add a complement function) |
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| Line 190: | Line 190: | ||
end |
end |
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ret[#ret + 1] = val |
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 == 0 then |
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error("no arguments passed to 'complement' (minimum is two)", 2) |
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elseif lim == 1 then |
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error("only one argument passed to 'complement' (minimum is two)", 2) |
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end |
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-- Now we know that we have at least two sets. |
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local ret = select(lim, ...) |
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checkType('complement', lim, ret, 'table') |
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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 |
end |
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end |
end |
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