Exporting list of lists in Google Earth Engine

Question

I have a list of lists (you can see on the pic), and would like to export it as .csv. I tried to convert it into feature collection, and then run the following lines:

var feature = ee.Feature(null, lossperyearperelevation1);
var featureCollection = ee.FeatureCollection([feature]);
Export.table.toDrive({
  collection: featureCollection,
  description: 'exportTableExample',
  fileFormat: 'CSV'});

it gives the following error: Error: Feature, argument 'metadata': Invalid type. Expected type: Dictionary. Actual type: List<List<Dictionary>>.

I am confused if it is a list of list, and how to export it in .csv. How can I solve this problem?

the link for the sample code is here: https://code.earthengine.google.com/40c2c24233a6119ee577fb05dd86a14e

Answer 1

The grouped reducer output are always a bit messy. Here is a way to rework your output to a feature collection:

// rework output
var featureCollection = ee.FeatureCollection(lossperyearperelevation1.map(function(element){
  element = ee.Dictionary(element); // cast
  var list = ee.List(element.get('groups'));
  var feats = ee.FeatureCollection(list.map(function(listEl){
    var dict = ee.Dictionary(listEl);
    return ee.Feature(null, dict);
  }));
  return feats
})).flatten();

As there are not so many comments in your code, it is hard to understand what your goal is. Link code