> For the complete MongoDB documentation index, see www.mongodb.com/docs/llms.txt

# $rtrim  (expression operator)

## Definition

Removes whitespace characters, including null, or the specified characters from the end of a string.

[`$rtrim`](https://www.mongodb.com/docs/manual/reference/operator/aggregation/rtrim.md#mongodb-expression-exp.-rtrim) has the following syntax:

```javascript
{ $rtrim: { input: <string>,  chars: <string> } }
```

The [`$rtrim`](https://www.mongodb.com/docs/manual/reference/operator/aggregation/rtrim.md#mongodb-expression-exp.-rtrim) takes a document with the following fields:

| Field | Description |
| --- | --- |
| `input` | The string to trim. The argument can be any valid [expression](https://www.mongodb.com/docs/manual/reference/mql/expressions.md#std-label-aggregation-expressions) that resolves to a string. For more information on expressions, see [Expressions.](https://www.mongodb.com/docs/manual/reference/mql/expressions.md#std-label-aggregation-expressions) |
| `chars` | Optional. The character(s) to trim from the end of the `input`. The argument can be any valid [expression](https://www.mongodb.com/docs/manual/reference/mql/expressions.md#std-label-aggregation-expressions) that resolves to a string. The [`$rtrim`](https://www.mongodb.com/docs/manual/reference/operator/aggregation/rtrim.md#mongodb-expression-exp.-rtrim) operator breaks down the string into individual UTF [code point](http://www.unicode.org/glossary/#code_point) to trim from `input`. If unspecified, [`$rtrim`](https://www.mongodb.com/docs/manual/reference/operator/aggregation/rtrim.md#mongodb-expression-exp.-rtrim) removes whitespace characters, including the null character. For the list of whitespace characters, see [Whitespace Characters.](https://www.mongodb.com/docs/manual/reference/operator/aggregation/rtrim.md#std-label-rtrim-white-space) |

**See also:**

- [`$ltrim`](https://www.mongodb.com/docs/manual/reference/operator/aggregation/ltrim.md#mongodb-expression-exp.-ltrim)

- [`$trim`](https://www.mongodb.com/docs/manual/reference/operator/aggregation/trim.md#mongodb-expression-exp.-trim)

## Behavior

- By default, [`$rtrim`](https://www.mongodb.com/docs/manual/reference/operator/aggregation/rtrim.md#mongodb-expression-exp.-rtrim) removes whitespace, including the null character, from the end of the input string:

  | Example | Results |
  | --- | --- |
  | `{ $rtrim: { input: "  \n good  bye \t  " } }` | `"  \n good  bye"` |

- You can override the default characters to trim using the `chars` field.

  For example, the following trims any `g` and `e` from the end of the input string. Since the input ends with a whitespace, neither character can be trimmed from the end of the string.

  | Example | Results |
  | --- | --- |
  | `{ $rtrim: { input: "ggggoodbyeeeee   ", chars: "ge" } }` | `"ggggoodbyeeeee   "` |

- If overriding the default characters to trim, you can explicitly include the whitespace character(s) to trim in the `chars` field.

  For example, the following trims any space or `e` from the end of the input string.

  | Example | Results |
  | --- | --- |
  | `{ $rtrim: { input: " ggggoodbyeeeee   ", chars: "e " } }` | `" ggggoodby"` |

### Whitespace Characters

By default, [`$rtrim`](https://www.mongodb.com/docs/manual/reference/operator/aggregation/rtrim.md#mongodb-expression-exp.-rtrim) removes the following whitespace, including the null character:

| Unicode | Escape sequence | Description |
| --- | --- | --- |
| U+0000 | '0' | Null character |
| U+0020 | ' ' | Space |
| U+0009 | 't' | Horizontal tab |
| U+000A | 'n' | Line feed/new line |
| U+000B | 'v' | Vertical tab |
| U+000C | 'f' | Form feed |
| U+000D | 'r' | Carriage return |
| U+00A0 |  | Non-breaking space |
| U+1680 |  | Ogham space mark |
| U+2000 |  | En quad |
| U+2001 |  | Em quad |
| U+2002 |  | En space |
| U+2003 |  | Em space |
| U+2004 |  | Three-per-em space |
| U+2005 |  | Four-per-em space |
| U+2006 |  | Six-per-em space |
| U+2007 |  | Figure space |
| U+2008 |  | Punctuation space |
| U+2009 |  | Thin space |
| U+200A |  | Hair space |

## Limitations

Starting in MongoDB 8.3, the length of the string you provide to `chars` is limited to 4096 characters. If you provide a string longer than 4096 characters, MongoDB returns an error similar to the following:

```none
$trim/$ltrim/$rtrim requires 'chars' to be not greater than 4096 bytes, got
<length> bytes instead.
```

## Example

Consider an `inventory` collection with the following documents:

```javascript
db.inventory.insertMany( [
   { _id: 1, item: "ABC1", quarter: "13Q1", description: " product 1" },
   { _id: 2, item: "ABC2", quarter: "13Q4", description: "product 2 \n The product is in stock.  \n\n  " },
   { _id: 3, item: "XYZ1", quarter: "14Q2", description: null }
] )
```

The following operation uses the [`$rtrim`](https://www.mongodb.com/docs/manual/reference/operator/aggregation/rtrim.md#mongodb-expression-exp.-rtrim) operator to remove trailing whitespace from the `description` field:

```javascript
db.inventory.aggregate([
   { $project: { item: 1, description: { $rtrim: { input: "$description" } } } }
])
```

The operation returns the following results:

```javascript
{ _id: 1, item: "ABC1", description: " product 1" }
{ _id: 2, item: "ABC2", description: "product 2 \n The product is in stock." }
{ _id: 3, item: "XYZ1", description: null }
```