根据嵌套的json值对lua表进行排序

Question

在redis中我们有一个键值对，它由一个带有JSON对象的键作为具有各种信息的值组成;

"node:service:i-01fe0d69c343734" : 
"{\"port\":\"32781\", 
\"version\":\"3.0.2\", 
\"host-instance-id\":\"i-01fe0d69c2243b366\", 
\"last-checkin\":\"1492702508\", 
\"addr\":\"10.0.0.0\", 
\"host-instance-type\":\"m3.large\"}" 

是否有可能基于该last-checkin时间值的表进行排序？

Answer 1

这里是我的问题的解决方案，使用快速排序算法，做你输入的一点校正（我的理解它）之前：

----------------------------------------------------- 
local json = require("json") 

function quicksort(t, sortname, start, endi) 
    start, endi = start or 1, endi or #t 
    sortname = sortname or 1 
    if(endi - start < 1) then return t end 
    local pivot = start 
    for i = start + 1, endi do 
    if t[i][sortname] <= t[pivot][sortname] then 
     local temp = t[pivot + 1] 
     t[pivot + 1] = t[pivot] 
     if(i == pivot + 1) then 
     t[pivot] = temp 
     else 
     t[pivot] = t[i] 
     t[i] = temp 
     end 
     pivot = pivot + 1 
    end 
    end 
    t = quicksort(t, sortname, start, pivot - 1) 
    return quicksort(t, sortname, pivot + 1, endi) 
end 
--------------------------------------------------------- 

-- I manually added delimeter "," 
-- and name "node:service..." must be different 
str = [[ 
{ 
"node:service:i-01fe0d69c343731" : 
"{\"port\":\"32781\", 
\"version\":\"3.0.2\", 
\"host-instance-id\":\"i-01fe0d69c2243b366\", 
\"last-checkin\":\"1492702506\", 
\"addr\":\"10.0.0.0\", 
\"host-instance-type\":\"m3.large\"}" 
, 
"node:service:i-01fe0d69c343732" : 
"{\"port\":\"32781\", 
\"version\":\"3.0.2\", 
\"host-instance-id\":\"i-01fe0d69c2243b366\", 
\"last-checkin\":\"1492702508\", 
\"addr\":\"10.0.0.0\", 
\"host-instance-type\":\"m3.large\"}" 
, 
"node:service:i-01fe0d69c343733" : 
"{\"port\":\"32781\", 
\"version\":\"3.0.2\", 
\"host-instance-id\":\"i-01fe0d69c2243b366\", 
\"last-checkin\":\"1492702507\", 
\"addr\":\"10.0.0.0\", 
\"host-instance-type\":\"m3.large\"}" 
, 
"node:service:i-01fe0d69c343734" : 
"{\"port\":\"32781\", 
\"version\":\"3.0.2\", 
\"host-instance-id\":\"i-01fe0d69c2243b366\", 
\"last-checkin\":\"1492702501\", 
\"addr\":\"10.0.0.0\", 
\"host-instance-type\":\"m3.large\"}" 
} 
]] 

-- remove unnecessary \ 

str = str:gsub('"{','{'):gsub('}"','}'):gsub('\\"','"') 

local t_res= json.decode(str) 
-- prepare table before sorting 
local t_indexed = {} 
for k,v in pairs(t_res) do 
    v["node-service"] = k 
    t_indexed[#t_indexed+1] = v 
end 
-- algoritm quicksort realised only for indexed table 
local t_sort= quicksort(t_indexed, "last-checkin") 

for k,v in pairs(t_sort) do 
    print(k , v["node-service"] , v["port"], v["version"], v["host-instance-id"], v["last-checkin"] , v["addr"], v["host-instance-type"] ) 
end 

控制台：

1 node:service:i-01fe0d69c343734 32781 3.0.2 i-01fe0d69c2243b366 1492702501 10.0.0.0 m3.large 
2 node:service:i-01fe0d69c343731 32781 3.0.2 i-01fe0d69c2243b366 1492702506 10.0.0.0 m3.large 
3 node:service:i-01fe0d69c343733 32781 3.0.2 i-01fe0d69c2243b366 1492702507 10.0.0.0 m3.large 
4 node:service:i-01fe0d69c343732 32781 3.0.2 i-01fe0d69c2243b366 1492702508 10.0.0.0 m3.large