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Iterate

From NoSQLZoo
Revision as of 23:43, 8 April 2018 by 40166222 (talk | contribs)
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MongoDB's find() method returns a cursor object which can be iterated using while, hasNext() and next, or by using forEach().

Iterating countries in South America stored in the 'world' collection.

let cursor = db.world.find({continent:"South America"})
while (cursor.hasNext()) {
   printjson(cursor.next());
}
let cursor = db.world.find({continent:"South America"})
cursor.forEach(printjson);

Cursors can also be converted to other JavaScript collection types, such as arrays.
In the following example an array is used to find the nth record in a result as an alternative to .find().skip(n).limit(1)

Find the 3rd result of the previous example.

db.world.find({continent:"South America"}).toArray()[3]