lua:table

1.习惯上，Lua的下表从1开始，只有这样，才可以使用标准库的函数

--链表
list=nil
list={next=list,value="v"}
list={next=list,value=88}

local l=list
while l do
    print(l.value)
    l=l.next
end

--输出88 v

--队列
List={}
function List.new()
    return {first=0,last=-1}
end

function List.pushleft(list,value)
    local first=list.first-1
    list.first=first
    list[first]=value
end

function List.pushright(list,value)
    local last=list.last+1
    list.last=last
    list[last]=value
end

function List.popleft(list)
    local first=list.first
    if first>list.last then 
        error("list is empty")
    end
    local value=list[first]
    list[first]=nil --to allow garbage collection
    list.first=first+1
    return value
end

--遍历table
function set(list)
    local set={}
    for _,l in pairs(list) do
        print(l)
    end
end

list={"fun","bored","intre"}
set(list)

 

lines={
    lua_set=10,
    lua_get=24,
    lua_present=48,
}
--table.sort是对value进行排序
function pairsByKeys(t,f)
    local a={}
    for n in pairs(t) do table.insert(a,n) end
    table.sort(a,f)
    local i=0
    local iter=function()
        i=i+1
        if a[i]==nil then return nil
        else return a[i],t[a[i]] 
        end
    end
    return iter
end

for name,line in pairsByKeys(lines) do
    print(name,line)
end