mongo copy from one collection to another (on the same db)

Question

I have got mongo db called test and in this db two collections collection1 and collection1_backup. How to replace content of col

Answer 1

Better way would be to use .toArray()

 db.collection1.drop(); // Drop entire other collection

 // creates an array which can be accessed from "data"
 db.collection1_backup.find().toArray(function(err, data) {

      // creates a collection and inserting the array at once
      db.collection1.insert(data);
 });