---
type: "fhirpath-function"
title: "FHIRPath Function: exists"
function: "exists"
category: "Existence"
section: "5.1.2"
source: "fhirpath/functions.json"
---
# FHIRPath Function: exists
> This is a [scoped function](#scoped-functions): The `criteria` argument is evaluated for each item (setting `$this` and `$index` before each iteration); if any return `true` then the function returns `true`, otherwise `false`.

Returns `true` if the input collection has any items (optionally filtered by the criteria), and `false` otherwise.
This is the opposite of `empty()`, and as such is a shorthand for `empty().not()`. If the input collection is empty (`{ }`), the result is `false`.

Using the optional criteria can be considered a shorthand for `where(criteria).exists()`.

Note that a common term for this function is _any_.

The following examples illustrate some potential uses of the `exists()` function:

``` fhirpath
Patient.name.exists()
Patient.identifier.exists(use = 'official')
Patient.telecom.exists(system = 'phone' and use = 'mobile')
Patient.generalPractitioner.exists(resolve() is Practitioner)
```

The first example returns `true` if the `Patient` has any `name` elements.

The second example returns `true` if the `Patient` has any `identifier` elements that have a `use` element equal to `'official'`.

The third example returns `true` if the `Patient` has any `telecom` elements that have a `system` element equal to `'phone'` and a `use` element equal to `'mobile'`.

And finally, the fourth example returns `true` if the `Patient` has any `generalPractitioner` elements of type `Practitioner`.

<a name="fn-all"></a>
## Summary
- **Category**: Existence
- **Section**: `5.1.2`
- **Return Type**: `Boolean`
- **Empty Input Result**: `false`
- **Errors on Multiple Input**: `false`
## Description
Returns `true` if the input collection has any elements (optionally filtered by the criteria), and `false` otherwise. This is the opposite of `empty()`, and as such is a shorthand for `empty().not()`.
## Arguments
- `criteria` (optional): `expression` - Optional criteria to filter the elements
## Type Mapping
- `Any-Boolean`
## Example
```fhirpath
Patient.name.exists()
Patient.identifier.exists(use = 'official')
Patient.telecom.exists(system = 'phone' and use = 'mobile')
```