Redis - How to store the result of zrange query as another ordered set












0















For example I create a sorted set with this command: 



zadd key1 1 u1 2 u2 3 u3


Now I to query last 2 items and store under other key, say key2. I know that I need to query like this:



zrange key1 -2 -1


but I don't know how to store the result with key2. Sorry for noob question, I am new to Redis, just 2 hours :)






redis sortedset







share|improve this question



























    0















    For example I create a sorted set with this command: 



    zadd key1 1 u1 2 u2 3 u3


    Now I to query last 2 items and store under other key, say key2. I know that I need to query like this:



    zrange key1 -2 -1


    but I don't know how to store the result with key2. Sorry for noob question, I am new to Redis, just 2 hours :)






    redis sortedset







    share|improve this question

























      0












      0








      0








      For example I create a sorted set with this command: 



      zadd key1 1 u1 2 u2 3 u3


      Now I to query last 2 items and store under other key, say key2. I know that I need to query like this:



      zrange key1 -2 -1


      but I don't know how to store the result with key2. Sorry for noob question, I am new to Redis, just 2 hours :)






      redis sortedset







      share|improve this question














      For example I create a sorted set with this command: 



      zadd key1 1 u1 2 u2 3 u3


      Now I to query last 2 items and store under other key, say key2. I know that I need to query like this:



      zrange key1 -2 -1


      but I don't know how to store the result with key2. Sorry for noob question, I am new to Redis, just 2 hours :)






      redis sortedset




      redis sortedset






      share|improve this question













      share|improve this question











      share|improve this question




      share|improve this question










      asked Nov 21 '18 at 12:36









      NarekNarek

      18.2k55174310




      18.2k55174310
























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          While Redis does not have a built-in command to do that, you can get away easily and safely with a Lua script. This one is a just a little extra tricky because the reply from ZRANGE needs swapping between the pairs of member-score to be used as input for ZADD.



          local src, dst = KEYS[1], KEYS[2]
          
local from, to = ARGV[1], ARGV[2]
          

          
local payload = redis.call('ZRANGE', src, from, to, 'WITHSCORES')
          

          
for i = 1, #payload/2 do
          
  payload[2*i-1], payload[2*i] = payload[2*i], payload[2*i-1]
          
end
          

          
return redis.call('ZADD', dst, unpack(payload))


          For details on how to use Lua in Redis see the EVAL commmand.






          share|improve this answer























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            1 Answer
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            1 Answer
            1






            active

            oldest

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            active

            oldest

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            0














            While Redis does not have a built-in command to do that, you can get away easily and safely with a Lua script. This one is a just a little extra tricky because the reply from ZRANGE needs swapping between the pairs of member-score to be used as input for ZADD.



            local src, dst = KEYS[1], KEYS[2]
            
local from, to = ARGV[1], ARGV[2]
            

            
local payload = redis.call('ZRANGE', src, from, to, 'WITHSCORES')
            

            
for i = 1, #payload/2 do
            
  payload[2*i-1], payload[2*i] = payload[2*i], payload[2*i-1]
            
end
            

            
return redis.call('ZADD', dst, unpack(payload))


            For details on how to use Lua in Redis see the EVAL commmand.






            share|improve this answer




























              0














              While Redis does not have a built-in command to do that, you can get away easily and safely with a Lua script. This one is a just a little extra tricky because the reply from ZRANGE needs swapping between the pairs of member-score to be used as input for ZADD.



              local src, dst = KEYS[1], KEYS[2]
              
local from, to = ARGV[1], ARGV[2]
              

              
local payload = redis.call('ZRANGE', src, from, to, 'WITHSCORES')
              

              
for i = 1, #payload/2 do
              
  payload[2*i-1], payload[2*i] = payload[2*i], payload[2*i-1]
              
end
              

              
return redis.call('ZADD', dst, unpack(payload))


              For details on how to use Lua in Redis see the EVAL commmand.






              share|improve this answer


























                0












                0








                0







                While Redis does not have a built-in command to do that, you can get away easily and safely with a Lua script. This one is a just a little extra tricky because the reply from ZRANGE needs swapping between the pairs of member-score to be used as input for ZADD.



                local src, dst = KEYS[1], KEYS[2]
                
local from, to = ARGV[1], ARGV[2]
                

                
local payload = redis.call('ZRANGE', src, from, to, 'WITHSCORES')
                

                
for i = 1, #payload/2 do
                
  payload[2*i-1], payload[2*i] = payload[2*i], payload[2*i-1]
                
end
                

                
return redis.call('ZADD', dst, unpack(payload))


                For details on how to use Lua in Redis see the EVAL commmand.






                share|improve this answer













                While Redis does not have a built-in command to do that, you can get away easily and safely with a Lua script. This one is a just a little extra tricky because the reply from ZRANGE needs swapping between the pairs of member-score to be used as input for ZADD.



                local src, dst = KEYS[1], KEYS[2]
                
local from, to = ARGV[1], ARGV[2]
                

                
local payload = redis.call('ZRANGE', src, from, to, 'WITHSCORES')
                

                
for i = 1, #payload/2 do
                
  payload[2*i-1], payload[2*i] = payload[2*i], payload[2*i-1]
                
end
                

                
return redis.call('ZADD', dst, unpack(payload))


                For details on how to use Lua in Redis see the EVAL commmand.







                share|improve this answer












                share|improve this answer



                share|improve this answer










                answered Nov 21 '18 at 13:38









                Itamar HaberItamar Haber

                28.8k43760




                28.8k43760
































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