text: var _ = require('underscore');
  var tab = [1,2,3,4,5];
  _.each(tab,function(value, index, array){
      console.log(value, index, array)
  });
  
  var person = {};
  person.friends = {
      name1: 'obj name1',
      name2: 'obj name2',
      name3: 'obj name3',
      name4: 'obj name4'
  };
  
  _.each(['name4', 'name2'], function(name, index, array){
      console.log(this[name], index, array, this);
  }, person.friends);
  
  console.log('Map',_.map([1, 2, 3], function(num){ return num * 3; }) );
  