// Example: $set in Arrays

// Set a new array or update an existing array in a document.

db.users.updateOne({ name: 'Alice' }, { $set: { hobbies: ['Reading', 'Painting'] } });

​

// Example: $set in Objects

// Set a new field or update an existing field with an object.

db.users.updateOne({ name: 'Bob' }, { $set: { details: { gender: 'Male', occupation: 'Engineer' } } });

​

// Example: $set in Array of Objects

// Set a new field or update an existing field that is an array of objects.

db.users.updateOne(

  { name: 'Charlie', 'skills.language': 'JavaScript' },

  { $set: { 'skills.$.level': 'Intermediate' } }

);