MongoDB $pull Operator

The $pull operator in MongoDB removes matching values from an array field during updates, enabling in-place modification of arrays without rewriting the entire document.

• Removes all instances of specified values from an array.
• Works on arrays inside embedded (nested) documents.
• Leaves the array unchanged if no matching value is found.
• Performs in-place updates; errors may still occur if the field type is invalid or the query is incorrect.

Syntax

{ $pull: { <field1>: <value|condition>, <field2>: <value|condition>, ... } }

• <field1>, <field2>, ... specifies the array fields from which values should be removed.
• <value | condition> defines the value or matching condition to pull from each array.

Examples of $pull Operator

To understand MongoDB $pull Operator we need a collection and some documents on which we will perform various operations and queries. Here we will consider a collection called contributor.

Example 1: Removing a Specific value

Remove the skill "Java" from all contributors who have it.

db.contributor.updateMany(
 { skills: "Java" },
 { $pull: { skills: "Java" } }
)

Output:

Example 2: Removing Multiple Values

Remove the skills "JavaScript" and "Python" from all contributors who have them.

db.contributor.updateMany(
 { skills: { $in: ["JavaScript", "Python"] } },
 { $pull: { skills: { $in: ["JavaScript", "Python"] } } }
)

Output:

Example 3: Removing Based on Condition

Remove skills that are shorter than 5 characters from all contributors.

db.contributor.updateMany(
 {},
 { $pull: { skills: { $regex: "^.{1,4}$" } } }
)

The regex "^.{1,4}$" matches strings of length 1 to 4, so $pull removes skills shorter than 5 characters.

Output:

Usage of $pull Operator

Here are some uses of $pull operator:

• Remove specific elements from arrays for data cleanup and customization.
• Apply conditions to match and remove elements or embedded documents within array fields.
• Remove exact values or documents that match specified fields and values.
• Use with update methods like updateMany() and findAndModify() as needed.