Question

I want to create an array by extracting the dates of some other array and then comma separate the values into a string.

      array.push({date:created_at,username:user});
      for (i in array) {
      var combined=new array();
      combined = array[i].date;
                }   
      console.log(combined);

I am new to javascript and hard to follow in arrays.Thanks !! Can anyone also recommend me a good book for javascript?

Answer 1

Try this

var originalArray = [{date:"2012-01-01", username: "first"}, {date:"2012-01-02", username: "second"}];

// First step: Get a dateArray with only the dates
var dateArray = [];
for (var i in originalArray) {
    dateArray.push(originalArray[i].date);
}   

// Or if you prefer to cut a few lines
// dateArray = originalArray.map(function(x) { return x.date; } );

// Second step: Get it as a comma separated string
var datesString = dateArray.join(",");

console.log(dateArray); // ["2012-01-01","2012-01-02"]
console.log(datesString); // 2012-01-01,2012-01-02

One of the more popular books is “Javascript The Good Parts” by Douglas Crockford
http://www.amazon.com/JavaScript-Good-Parts-Douglas-Crockford/dp/0596517742