# ee.FeatureCollection.makeArray

Add a 1-D Array to each feature in a collection by combining a list of properties for each feature into a 1-D Array. All of the properties must be numeric values. If a feature doesn't contain all of the named properties, or any of them aren't numeric, the feature will be dropped from the resulting collection.

<br />

| Usage | Returns |
|---|---|
| `FeatureCollection.makeArray(properties, *name*)` | FeatureCollection |

| Argument | Type | Details |
|---|---|---|
| this: `collection` | FeatureCollection | The input collection from which properties will be selected. |
| `properties` | List | The properties to select. |
| `name` | String, default: "array" | The name of the new array property. |

## Examples

### Code Editor (JavaScript)

```javascript
// FeatureCollection of power plants in Belgium.
var fc = ee.FeatureCollection('WRI/GPPD/power_plants')
            .filter('country_lg == "Belgium"');

// A list of feature properties to combine into an array
// (power generation by year).
var properties = ['gwh_2013', 'gwh_2014', 'gwh_2015', 'gwh_2016'];

// Add array of power-generation-by-year property to features.
fc = fc.makeArray(properties, 'gwh_by_year');

print('FeatureCollection with array of selected properties added', fc);
print('See example of new "gwh_by_year" property', fc.first().toDictionary());
```
Python setup

See the [Python Environment](https://developers.google.com/earth-engine/guides/python_install) page for information on the Python API and using
`geemap` for interactive development.

```python
import ee
import geemap.core as geemap
```

### Colab (Python)

```python
# FeatureCollection of power plants in Belgium.
fc = ee.FeatureCollection('WRI/GPPD/power_plants').filter(
    'country_lg == "Belgium"')

# A list of feature properties to combine into an array
# (power generation by year).
properties = ['gwh_2013', 'gwh_2014', 'gwh_2015', 'gwh_2016']

# Add array of power-generation-by-year property to features.
fc = fc.makeArray(properties, 'gwh_by_year')

display('FeatureCollection with array of selected properties added:', fc)
display('See example of new "gwh_by_year" property:', fc.first().toDictionary())
```