---
type: "fhirpath-function"
title: "FHIRPath Function: select"
function: "select"
category: "Filtering and projection"
section: "5.2.2"
source: "fhirpath/functions.json"
---
# FHIRPath Function: select
> This is a [scoped function](#scoped-functions): The `projection` argument is evaluated for each item (setting `$this` and `$index` before each iteration); and the results are included in the output collection.

Evaluates the `projection` expression for each item in the input collection. The result of each evaluation is added to the output collection. If the evaluation results in a collection with multiple items, all items are added to the output collection (collections resulting from evaluation of `projection` are _flattened_). This means that if the evaluation for an item results in the empty collection (`{ }`), no item is added to the result, and that if the input collection is empty (`{ }`), the result is empty as well.

``` fhirpath
Bundle.entry.select(resource as Patient)
```

This example results in a collection with only the patient resources from the bundle.

``` fhirpath
Bundle.entry.select((resource as Patient).telecom.where(system = 'phone'))
```

This example results in a collection with all the telecom elements with system of `phone` for all the patients in the bundle.

``` fhirpath
Patient.name.where(use = 'usual').select(given.first() + ' ' + family)
```

This example returns a collection containing, for each "usual" name for the Patient, the concatenation of the first given and family names.

<a name="instance-selector"></a>
## Summary
- **Category**: Filtering and projection
- **Section**: `5.2.2`
- **Return Type**: `collection`
- **Empty Input Result**: `empty`
- **Errors on Multiple Input**: `false`
## Description
Evaluates the `projection` expression for each item in the input collection. The result of each evaluation is added to the output collection. If the evaluation results in a collection with multiple items, all items are added to the output collection (collections resulting from evaluation of `projection` are _flattened_).
## Arguments
- `projection`: `expression` - Expression to project each element
## Type Mapping
- `Any-Any`
## Example
```fhirpath
Patient.name.where(use = 'usual').select(given.first() + ' ' + family)
```