How to sort an Array by the content of its documents in MongoDB

Question

I run the following command from a JavaScript function in the MongoDB-Shell:

db._adminCommand( {listDatabases: 1}).databases

That gives me:

[
    {
        "name" : "local",
        "sizeOnDisk" : 83886080,
        "empty" : false
    },
    {
        "name" : "time",
        "sizeOnDisk" : 83886080,
        "empty" : false
    },
    {
        "name" : "event",
        "sizeOnDisk" : 83886080,
        "empty" : false
    },
    {
        "name" : "admin",
        "sizeOnDisk" : 1,
        "empty" : true
    },
    {
        "name" : "test",
        "sizeOnDisk" : 1,
        "empty" : true
    }
]

Is it somehow possible to sort the documents in that array by their value in the field name?

Finally I'd like to get:

[
    {
        "name" : "admin",
        "sizeOnDisk" : 1,
        "empty" : true
    },
    {
        "name" : "event",
        "sizeOnDisk" : 83886080,
        "empty" : false
    },
    {
        "name" : "local",
        "sizeOnDisk" : 83886080,
        "empty" : false
    },
    {
        "name" : "test",
        "sizeOnDisk" : 1,
        "empty" : true
    },
    {
        "name" : "time",
        "sizeOnDisk" : 83886080,
        "empty" : false
    }
]

as neil-lunn referenced the link: run command return a document as result and you cant deal with it like a cursor You could use javascript to do the job: var result = db._adminCommand( {listDatabases: 1}).databases; result.sort(function(a,b) { var nameA = a.name.toLowerCase(); var nameB = b.name.toLowerCase(); //sort string ascending if (nameA < nameB) return -1 if (nameA > nameB) return 1 return 0; }); — Disposer, Jan 23 '15 at 10:39

Alex Barannikov · Accepted Answer · 2015-01-23T11:21:43.070

2

Use sort method:

db._adminCommand( {listDatabases: 1}).databases.sort(function(item1, item2){return item1.name > item2.name})

edited Jan 23 '15 at 11:21

answered Jan 23 '15 at 09:56

Alex Barannikov

304
2
8

1

databases is a object and not a cursor, you cant use sort() on it – Disposer Jan 23 '15 at 10:40
1

Yes, you're right. But we can Use Array.sort() since databases is an Array: db._adminCommand( {listDatabases: 1}).databases.sort(function(item1, item2){return item1.name > item2.name}); – Alex Barannikov Jan 23 '15 at 11:18
update your answer to your comment and you will get my +1 for sure – Disposer Jan 23 '15 at 11:21

How to sort an Array by the content of its documents in MongoDB

1 Answers1