Lua：合并键和输出键不应该在表中具有重复值

Question

我有一张桌子

 
test = {a= {1,2}, b= {1},c= {2,3}}

我希望输出像。

test_out = {ab={1,2}, bc = {1,2,3}, ac={1,2,3}}

Answer 1

显然你想要的是设置操作。这是一种没有任何库的方法：

local test = {a = {1, 2}, b = {1}, c = {2, 3}}

local keys = {}
for k,_ in pairs(test) do keys[#keys+1] = k end
table.sort(keys)

local result = {}
local t1, t2, r, found

for i=1,#keys-1 do
  for j=i+1,#keys do
    t1 = test[keys[i]]
    t2 = test[keys[j]]
    r, found = {}, {}
    for k=1,#t1 do
      found[t1[k]] = true
      r[k] = t1[k]
    end
    for k=1,#t2 do
      if not found[t2[k]] then
        r[#r+1] = t2[k]
      end
    end
    result[keys[i] .. keys[j]] = r
  end
end

结果在result表中。如果您可以使用pl.Set之类的集合库，则可以使用更少的代码执行此操作：

local test = {a = {1, 2}, b = {1}, c = {2, 3}}

local keys = {}
for k,_ in pairs(test) do keys[#keys+1] = k end
table.sort(keys)

local result = {}
local Set = require "pl.Set"

for i=1,#keys-1 do
  for j=i+1,#keys do
    result[keys[i] .. keys[j]] = Set.values(
      Set(test[keys[i]]) + Set(test[keys[j]])
    )
  end
end