node_redis get zrange withscores - node.js

Question

Does anybody know how can I get members with scores by node redis?
I tried something like this:
client.ZRANGE(key, 0, -1, withscores, function(err, replies) {
});
Thanks.

Answer 1

This code looks good. Check out the following link for retrieving what you want :
http://ricochen.wordpress.com/2012/02/28/example-sorted-set-functions-with-node-js-redis/
Added the code here from that link example in case it is ever removed.
var rc=require('redis').createClient();
var _=require('underscore');
rc.zincrby('myset', 1, 'usera');
rc.zincrby('myset', 5, 'userb');
rc.zincrby('myset', 3, 'userc');
rc.zrevrange('myset', 0, -1, 'withscores', function(err, members) {
// the resulting members would be something like
// ['userb', '5', 'userc', '3', 'usera', '1']
// use the following trick to convert to
// [ [ 'userb', '5' ], [ 'userc', '3' ], [ 'usera', '1' ] ]
// learned the trick from
// http://stackoverflow.com/questions/8566667/split-javascript-array-in-chunks-using-underscore-js
var lists=_.groupBy(members, function(a,b) {
return Math.floor(b/2);
});
console.log( _.toArray(lists) );
});
rc.quit();

Answer 2

Seems your code is right. The following is the syntax to get zrange.
without score:
redisClient.zrange(keyName,start,stop,function(err,result){
//result is array
// every index will give you member name
})
Ex :
redisClient.zrange("mySortedset",-1,-1,function(err,result){
//result is array
// every index will give you member name
})
with score:
redisClient.zrange(keyName,start,stop,'withscores',function(err,result){
//result is array
// here even index will hold member
// odd index will hold its score
})
Ex :
redisClient.zrange("mySortedset",-1,-1,'withscores',function(err,result){
//result is array
// here even index will hold member
// odd index will hold its score
})

Answer 3

I tried with the prior accepted answers but i could not get the result i want and later i tried with the following code and got appropriate result,
Original output:
[ 'player:522',
'19685',
'player:164',
'19594',
'player:807',
'19171',
'player:694',
'19165',
'player:905',
'19108',
'player:859',
'19087',
'player:432',
'18973',
'player:515',
'18831',
'player:163',
'18750',
'player:4',
'18552' ]
Expected output:
{
"player:522": "19685",
"player:164": "19594",
"player:807": "19171",
"player:694": "19165",
"player:905": "19108",
"player:859": "19087",
"player:432": "18973",
"player:515": "18831",
"player:163": "18750",
"player:4": "18552"
}
Solution:
redisClient.ZREVRANGE('daily', 1, 10, 'WITHSCORES', function(err, result) {
result = _.fromPairs(_.chunk(result, 2));
return res.status(200).json(result);
});

Answer 4

The right approach for versions ^2.0,
var args = [ key,to, from ];
redisClient.zrevrangebyscore(args,function(err,data){

Answer 5

Vanilla JS Solution
Redis call:
redisClient.zrange(keyName, start, stop, 'withscores', function(err, result) {
// result.reduce ... (See below)
}
Here is a Vanilla-JS solution that I came up with pretty quickly.
For me, personally, it does not make sense to import underscore or any other library to perform such an easy task:
result.reduce(function (a, c, i) {
var idx = i / 2 | 0;
if (i % 2) {
a[idx].score = c;
} else {
a[idx] = { id: c };
}
return a;
}, []);
Assuming this input:
['player1', 13, 'player2', 11, 'player4', 7, 'player3', 3, 'player5', 0]
This function yields:
[
{ id: 'player1', score: 13 },
{ id: 'player2', score: 11 },
{ id: 'player4', score: 7 },
{ id: 'player3', score: 3 },
{ id: 'player5', score: 0 }
]
Here is another one to transform the result into a two-dimensional array:
result.reduce(function (a, c, i) {
var idx = i / 2 | 0;
if (i % 2) {
a[idx].push(c);
} else {
a[idx] = [c];
}
return a;
}, []);
which produces the following array:
[
[ 'player1', 13 ],
[ 'player2', 11 ],
[ 'player4', 7 ],
[ 'player3', 3 ],
[ 'player5', 0 ]
]
One line lambda version:
result.reduce((a, c, i) => i % 2 ? (a[i / 2 | 0].data = c, a) : (a[i / 2 | 0] = { id: c }, a), []);

Answer 6

Vanilla JS reduce works well here.
const result = [
'player:522',
'19685',
'player:164',
'19594',
'player:807',
'19171',
'player:694',
'19165',
'player:905',
'19108',
'player:859',
'19087',
'player:432',
'18973',
'player:515',
'18831',
'player:163',
'18750',
'player:4',
'18552'
]
const map = result.reduce((map, k, i, res) => {
if (i % 2 !== 0) {
map[res[i - 1]] = Number(k);
}
return map;
}, {})
map is now:
{
'player:522': 19685,
'player:164': 19594,
'player:807': 19171,
'player:694': 19165,
'player:905': 19108,
'player:859': 19087,
'player:432': 18973,
'player:515': 18831,
'player:163': 18750.65468,
'player:4': 18552
}

Answer 7

var data = []
results.map((result, index) => {
if (index % 2 == 0) {
data.push(results[index] = { player: results[index], score: results[index+1] })
}
})
console.log(data)