1

I'm putting some dates into an array, and would like to have a second 'tier' in that array hold an order number associated with that date. It appears to be working correctly, but when I print out the array in the chrome console, I only see the first array of dates. If I access manually console.log(dateArray[1]['order_number']);, I see the expected information. Have I not constructed this array properly?

Thanks!

    for ( var u in valuesArr ) {

        //store the text seperator between the information and the order it is associated with
        var sep = "?order_num=";

        //store the string from which the information and order number will be extracted
        var str = valuesArr[u];

        //location of seperator
        var start = str.indexOf("?order_num=");

        var order_number = str.substring(start+sep.length);

        var current_date = valuesArr[u].substring(0, start);

        //date goes into "current_date" array
        current_date = current_date.split(" / ");

        //fashion it into a javascript date
        //month needs one subtracted
        dateArray[u] = new Date ( current_date[2], current_date[0]-1, current_date[1]);

        /*
        *to identify from which order this date derives, an order_number slot is created
        *underneath the sorted date slot
        *this is done so that when the html is reformatted to re-order the dates
        *the content associated with this date can be 'brought along with' it
        *as the its parent div's id contains the order number
        */
        dateArray[u]['order_number'] = order_number;

    }
    console.log(dateArray)//only outputs the array of dates
    console.log(dateArray[1]['order_number']);//outputs the order number
Improve this question

3 Answers 3

Reset to default
2

What you are doing with dateArray[u]['order_number'] = order_number; is adding a property to the Date object, not adding an element to the array.

To add an element to the array, use:

dateArray[u][1] = order_number;
Improve this answer
Sign up to request clarification or add additional context in comments.

8 Comments

dateArray[u]['order_number'] = order_number; is the same as saying dateArray[u].order_number = order_number;, meaning that the property order_number of the object dateArray[u] is set to the value of your variable order_number.
@Wex so is there any way to give it an index that's a string, or does it have to be a numeric index? Also, the way i'm doing it (and I'm not saying it's good or correct) does show up as I'd expect in the chrome console. any ideas why? thank you.
Array indexes must be numeric. What you're doing isn't necessarily wrong or bad, it's just probably not what you think you're doing. The console is probably saying, "I have an array here, so I will loop through it...this object is a date...it has a toString method...so I will call that method and display the result." It isn't going to look for random properties that you may have added to it.
so you cannot have "associative" arrays in javascript? or am i confused about what it means for an array to be "associative"? I thought it was just a key that's a string..
No, you cannot have associative arrays in javascript. Just a minute and I will find a reference to link to.
|
2

Don't trust developer consoles implicitly. There is no "correct" printing, because there's no standard.

If Chrome decides not to display the custom property on the object, that's up to Chrome. As long as your value is shown to be there with explicit testing, that's all that matters.

FWIW, you may get more desirable results with...

console.dir(dateArray)

The console.dir method will give you expandable objects so you can drill down and see your custom property.

Improve this answer

1 Comment

@wex this console.dir option shows everything exactly as i'd expect. how can it be demonstrated that it's adding a property to the date method. sorry to be obtuse, but i'm really confused about how it's happening.. I'm also kind of worried that I've done this before and it maybe just chrome's console that's understanding what i intend...
0

If valuesArr is an array, then using for (... in ...) will fail since this does an object iteration and will therefore grab lots of other elements of the array like length, indexOf, etc. etc.

Try using the traditional for loop instead:

for (var i = 0; i < valuesArr.length; i++) {
  // ...
}
Improve this answer

3 Comments

While you're right that for-in isn't the right tool, it won't grab native Array.prototype properties like .length, since they're non-enumerable. Only enumerable extensions will be encountered.
@amnotiam will definitely change to the for-loop. is it correct to assume it is actually the for-in loop that will grab these other elements and the for-in loop that will not? thanks for helping clear this up.
@thomas: for-in enumerates all enumerable properties, and doesn't guarantee any specific order. If you add enumerable properties to Array.prototype, the for-in will encounter those as well. The standard for loop is correct for iteration over numeric indices because it enforces specific properties and sequential order.

Start asking to get answers

Find the answer to your question by asking.

Ask question

Explore related questions

See similar questions with these tags.