list_algorithms

/***
 * List algorithms for enhacing List objects
 * 
 * Author: Rodrigo E. Principe
 * email: fitoprincipe82@gmail.com
 * License: MIT
 */

var help = {};

var remove_duplicates = function(list) {
  var newlist = ee.List([]);
  list = ee.List(list)
  var wrap = function(element, init) {
    init = ee.List(init);
    var contained = init.contains(element);
    
    return ee.Algorithms.If(contained, init, init.add(element));
  };
  return ee.List(list.iterate(wrap, newlist));
};

var get_from_dict = function(list, dict) {
  var empty = ee.List([])
  list = ee.List(list)
  dict = ee.Dictionary(dict)
  var values = ee.List(list.iterate(function(el, first) {
    var f = ee.List(first)
    var cond = dict.contains(el);
    return ee.Algorithms.If(cond, f.add(dict.get(el)), f)
  }, empty))
  return values
}

var intersect = function(list1, list2) {
  var newlist = ee.List([])
    var wrap = function(element, first) {
        first = ee.List(first)

        return ee.Algorithms.If(list2.contains(element), first.add(element), first)
    }
    return ee.List(list1.iterate(wrap, newlist))
}

// FILTERS

var regex = function(list, regex, flags) {
  list = ee.List(list)
  var fl = flags || null
  var i = ee.List([])
  var f = list.iterate(function(el, first){
    var f = ee.List(first)
    var e = ee.String(el);
    var matched = ee.List(e.match(regex, fl))
    return ee.Algorithms.If(matched.size().gt(0), f.add(el), f)
  }, i)
  return ee.List(f)
}

var filters = {regex: regex}

help['remove_duplicates'] = 'remove_duplicates(list)\n'+
                            'Remove duplicated values from a list object'
                            
help['get_from_dict'] = "get_from_dict(list, dict)\n"+
                        "Get a list of Dict's values from a list object. Keys must be unique"+
                        "list: list of keys\n"+
                        "dict: dict to get the values for list's keys\n"+
                        'return: ee.List'

help['itersection'] = "intersection(list1, list2)\n"+
                      "Return the intersection between two lists (common elements)"

help['filters'] = {'regex': 'filters.regex(list, regex, flags)\n'+
                            'Filter a list using a Regular Expression\n'+
                            'list: the list to filter\n'+
                            'regex: regular expression\n'+
                            'flags: flags for the RegEx'
                  }

exports.help = help
exports.remove_duplicates = remove_duplicates
exports.get_from_dict = get_from_dict
exports.filters = filters
exports.intersect = intersect
exports.options = ee.Dictionary(help).keys()