$rtrim (Trim Right)
Last updated: 2026-10-09
$rtrim (Trim Right)
$rtrim strips whitespace, or characters in the given chars set, from the right (end) of a string — the right-side variant of $trim. Great for trailing spaces, stray newlines, or end separators. chars defaults to whitespace and can be overridden with a custom set. Null or missing input yields null.
| Category | String |
|---|---|
| MongoDB Version | 1.0+ |
| Example Language | mongosh (Shell) |
📝 Syntax
{ $rtrim: { input: <string-expression>, chars: <charset> } }⚙️ Parameters
| input | Required; the string to process. |
|---|---|
| chars | Optional custom charset; whitespace by default. |
Returns：The right-trimmed string; null if input is null.
▶ Example
Run the commands below in your local mongosh (requires a running mongod):
// $rtrim: strip trailing newlines from log lines
db.logs.aggregate([
{ $project: { msg: { $rtrim: { input: '$raw', chars: '\r\n' } } } }
])Output：
{ "_id": 1, "msg": "done" }
{ "_id": 2, "msg": "ok" }📌 Notes
- Right end only; the left end stays untouched
- chars defaults to whitespace; override for custom endings
- Explicit chars can target trailing CRLF and similar
🏷️ Related Tags
💡 Related Cases
More hands-on cases coming soon.
📚 Related Tutorials
❓ FAQ
QCan trailing newlines be removed?
AYes — pass the CR/LF characters via chars.
QRight side only?
AYes — $rtrim only handles the string's end.
QHow does it combine with $ltrim?
AApply $ltrim then $rtrim — equivalent to $trim.
