Lua, Tables: merge values of duplicate keys and remove duplicates

问题

I've started fiddling a lot with lua recently, but I can't for my life figure this out.

Let's say I have a string that looks like this:

s = "a=x a=y b=z a=x"

I want to remove all duplicates and merge the values of duplicate keys into a table, so that I get:

t = {
a = {x,y},
b = {z},
}

I've been pondering about this for way too long. Any help is appreciated!

回答1:

Try this:

s="a=x a=y b=z a=x"

s=s.." "
t={}
for k,v in s:gmatch("(.-)=(.-)%s+") do
        if t[k]==nil then t[k]={} end
        t[k][v]=true
end

for k,v in pairs(t) do
        for z in pairs(v) do print(k,z) end
end

来源：https://stackoverflow.com/questions/16278657/lua-tables-merge-values-of-duplicate-keys-and-remove-duplicates