MongoDB: The Complete Guide/

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Update Documents - Part 4

Update Documents - Part 4

Learn and practice the $position, $slice, and $sort` operations while updating documents.

We'll cover the following...

$position operator

We use the $position operator to add a value at the specific position.We can only use it with $each operator.

{ 
  $push: { 
    <field>: { 
      $each: [ 
        <value>, 
        ...
      ],
      $position: <numeric value>
    } 
  } 
}

The $position value indicates the value on the zero-based index.

  • If the $position = 0, it pushes the values e from the start of the array.
  • If the $position > 0, it pushes the values from the provided index.
  • If the $position < 0, it looks at the index from reverse order, then pushes the values.

First, let’s insert a task with an array field to show the use of the $position.

db.tasks.insertOne({
      name: "Learn MongoDB Topic 1",
      tags: ["new", "learning", "MongoDB"]
});

Below is an example to insert tags ...