How to access datas from array in javascript

Question

I have a variable

var chartData = [];

I have entered a few datas in that variable as inside a for loop :

for(i=0;i<31;i++)
var newDate = new Date(firstDate);
                        newDate.setDate(newDate.getDate() + i);
                        i++;

                        chartData.push({
                            date: newDate,
                            visits: i 
                        });

The datas have entered in the array. but now i want to access those datas in a table again applying a for loop to make table rows. how to do that? I tried

document.write= " <tr> <td style='width:25%'>" + chartData.date[i] + " </td> <td style='width:25%'>" + chartData.visits[i] + "</td> <td style='width:25%'> " + chartData.visits[i]*i + " </td> <td style='width:25%'> " + chartData.visits[i]*chartData.visits[i] + " </td> </tr>";

But Couldnt get the datas... help needed. thankyou in advance..

You are increasing i twice in the loop. Was that indended? — Guffa
– Guffa, Commented Jan 2, 2015 at 15:41

bob-fornal · Accepted Answer · 2015-01-02 16:06:01Z

4

Close ... try ...

chartData[i].date 
chartData[i].visits
chartData[i].visits
chartData[i].visits*chartData[i].visits

The index is on chartData, not in the object inside; as you add objects to the array, the index increments against chartData.

edited Jan 2, 2015 at 16:06

answered Jan 2, 2015 at 15:40

bob-fornal

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Darin Dimitrov · Accepted Answer · 2015-01-02 15:40:14Z

1

chartData.date[i] should actually be chartData[i].date because its the chartData variable that represents the array.

answered Jan 2, 2015 at 15:40

Darin Dimitrov

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Ali insan Soyaslan · Accepted Answer · 2015-01-02 15:47:52Z

0

When you use push, push function sets the index automatically from zero. So your elements in tha array become like this:

chartData[0]={ date: newDate,visits: 0 }
chartData[1]={ date: newDate,visits: 1 }

so you can access elements from array:

 chartData[your_index].date 
 chartData[your_index].visits

answered Jan 2, 2015 at 15:47

Ali insan Soyaslan

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VSri58 · Accepted Answer · 2015-01-02 16:11:41Z

0

The syntax for accessing an Object value inside an array is

arrayname[index].Obj_Key

In your case, it should be

chartData[i].date

Here is a working DEMO for better understanding based on your code.

answered Jan 2, 2015 at 16:11

VSri58

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