hgetsmembers

Look up the contents of a Set in a Hash

Returns Array of values
Keys
  1. Hash
  2. Set containing fields from the Hash
Args None

Description

This script can be used to pull part of a Hash, based on values in a Set. This is useful when you want to maintain a particular Set of values for a specific purpose from a larger Hash object.

Example

The `groceries` Hash maintains counts of all the groceries we need. The `produce` Set keeps track of the fields in `groceries` that refer to fruits and vegetables. We can use this Lua script to pull the counts of just the produce from `groceries`.

> hset groceries bread 2
(integer) 1
> hset groceries apples 5
(integer) 1
> hset groceries oranges 6
(integer) 1
> hset groceries broccoli 1
(integer) 1
> sadd produce apples oranges broccoli
(integer) 3
> evalsha 700c06c5ce9835bf9eef2198c8bc4d268b3b5095 2 groceries produce
1) 1) "apples"
   2) "5"
2) 1) "broccoli"
   2) "1"
3) 1) "oranges"
   2) "6"

Source

local fields = redis.call("SMEMBERS", KEYS[2])
local values = redis.call("HMGET", KEYS[1], unpack(fields))
local result = {}
for i,k in ipairs(fields) do result[i] = {k, values[i]} end
return result

SHA

700c06c5ce9835bf9eef2198c8bc4d268b3b5095

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Last updated 30 Jul 2014.

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