Sort json based on length of an array

Question

I am trying to sort a feed that I have called in using Jquery.ajax. I'm trying to sort it by the number of values in an array within the feed.

For example, in this feed, I want to sort it by # of NFL teams in descending, so it would be re-sorted to California, New Jersey, Massachusetts:

[
   {
      "title":"New Jersey",
      "NFLteams":[
         {
            "Name":"Jets",
            "Conference":"AFC",
         },
         {
            "Name":"Giants",
            "Conference":"NFC",
         }
         ]
   },
   {
      "title":"Massachusetts",
      "NFLteams":[
         {
            "Name":"Patriots",
            "Conference":"AFC",
         }
         ]
   },
   {
      "title":"California",
      "NFLteams":[
         {
            "Name":"Raiders",
            "Conference":"AFC",
         },
         {
            "Name":"49ers",
            "Conference":"NFC",
         },
         {
            "Name":"Chargers",
            "Conference":"AFC",
         }
         ]
   }
]

I've tried code like this (from this thread Sorting an array of JavaScript objects), but it doesn't work (even if I make it NFLteams.length):

   var sort_by = function(field, reverse, primer){
   var key = function (x) {return primer ? primer(x[field]) : x[field]};

   return function (a,b) {
      var A = key(a), B = key(b);
      return ( (A < B) ? -1 : ((A > B) ? 1 : 0) ) * [-1,1][+!!reverse];                  
   }
   }
   data.sort(sort_by('NFLteams', false, function(a){return a.toUpperCase()}))

Any suggestions on how I can sort by the # of values in the array? Thanks to anyone who can help or point me in the right direction.

well, if those values are stored and fetched from DB would be easier to COUNT and compare then sort, just an idea. — Venzentx, Sep 02 '13 at 15:49

score 4 · Answer 1 · answered Sep 02 '13 at 15:54

4

Your method seems to work if you use the length property of the array:

data.sort(sort_by('NFLteams', false, function(a){return a.length}))

See JsBin: http://jsbin.com/eWafEMe/1/edit

answered Sep 02 '13 at 15:54

Tibos

27,507
4
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score 1 · Answer 2 · answered Sep 02 '13 at 15:52

1

Simple function like this will do the trick.

data.sort(function(a,b){
     return b.NFLteams.length - a.NFLteams.length;
});

http://jsfiddle.net/x9d2J/

answered Sep 02 '13 at 15:52

Yury Tarabanko

44,270
9
84
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score 1 · Answer 3 · answered Sep 02 '13 at 15:52

in your sort function reverse the comparison to return in descending order:

.sort(function(team1, team2) {
    return team2.NFLteams.length - team1.NFLteams.length;
});

or multiply the result by -1:

.sort(function(team1, team2) {
    return -1 * (team1.NFLteams.length - team2.NFLteams.length);
});

See the console output from this fiddle

score 0 · Answer 4 · answered Sep 02 '13 at 15:49

0

You can try underscore's sortBy:

_.sortBy(i, function(team){ return team['NFLteams'].length }).reverse();

where i is your input array.

fiddle: http://jsfiddle.net/kMbsW/

answered Sep 02 '13 at 15:49

cr0

617
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17

Sort json based on length of an array

4 Answers4