How to say… match when field is a number… in mongodb?

Question

So I have a field called \'city\' in my results...the results are corrupted, some times it\'s an actual name, sometimes it\'s a number. The following code displays all the recor

Answer 1

db.zips.aggregate([
    {$project : {city:{$substr:["$city",0,1]},pop:1}},
    {$group:{_id:"$city",sumPop:{$sum:"$pop"}}},
    {$sort : {_id : 1}}, 
    {$match:{_id : {$regex:/\d/}} },
    {$group:{_id:"id",sumPop:{$sum:"$sumPop"}}},
]);