---
type: "fhirpath-function"
title: "FHIRPath Function: trim"
function: "trim"
category: "Additional String Functions"
section: "5.7.5"
source: "fhirpath/functions.json"
---
# FHIRPath Function: trim
{: .stu }

The trim function trims whitespace characters from the beginning and ending of the input string, with whitespace characters as defined in the [Whitespace](#whitespace) lexical category.
{:.stu}

If the input is empty, the result is empty.
{:.stu}
## Summary
- **Category**: Additional String Functions
- **Section**: `5.7.5`
- **Return Type**: `String`
- **Empty Input Result**: `empty`
- **Errors on Multiple Input**: `true`
## Description
Returns the input string with leading and trailing whitespace removed.
## Arguments
- none
## Type Mapping
- `String-String`
## Example
```fhirpath
'  abc  '.trim() // 'abc'
'\tabc\n'.trim() // 'abc'
```