mongodb - How could I sort the items of a array and update to the original document -

i want sort array records , remove " ", " " items containing white space.

how aggregation.

this rough idea, not working

pipeline = [   {'$unwind': '$records'}   { '$sort':        "records.date": 1    } ]   db[source_collection].runcommand('aggregate',   pipeline: pipeline   allowdiskuse: true)     

sample document format

{   "_id": "0005dc158e68b0a2e4f2a8d96ca733f1",   "records": [     {       "date": new date("2012-12-04t08:00:00+0800"),       "items": [         "               ",         "4659           ",         "463            "       ]     },     {       "date": new date("2012-12-01t08:00:00+0800"),       "items": [         "               ",         "4658           "       ]     },     {       "date": new date("2012-10-18t08:00:00+0800"),       "items": [         "               ",         "78900          "       ]     },     {       "date": new date("2012-08-07t08:00:00+0800"),       "items": [         "               ",         "5230           "       ]     }   ],   "gender": "f",   "birthday": new date("1990-01-01t08:00:00+0800"),   "birthday_type": "d" } 

for sorting records array date check following aggregation query :

db.collectionname.aggregate({"$unwind":"$records"},{"$sort":{"records.date":1}}).pretty()  

and changing items array value need write programming code using mongo bulk write following script update every items array value check below :

var bulk = db.collectionname.initializeorderedbulkop(); var counter = 0; db.collectionname.find({         "records": {             "$exists": true         }     }).foreach(function(data) {         for(var ii = 0; ii < data.records.length; ii++) {             var items = data.records[ii].items;             var arr = [];             for(var j = 0; j < items.length; j++) {                 arr[j] = data.records[ii].items[j].trim()             }             var updoc = {                 "$set": {}             };             var updatekey = "records." + ii + ".items";             updoc["$set"][updatekey] = arr;             // queue update             bulk.find({                 "_id": data._id             }).update(updoc);             counter++;             // drain , re-initialize every 1000 update statements             if(counter % 1000 == 0) {                 bulk.execute();                 bulk = db.collectionname.initializeorderedbulkop();             }         }     })     // add rest in queue if(counter % 1000 != 0) bulk.execute();