Comparing and combining arrays in Javascript

Question

I have three arrays:

var dates = ['07/31/2013', '08/01/2013', '08/02/2013', '08/03/2013', '08/04/2013', '08/05/2013', '08/06/2013', '08/07/2013'];

The dates array contains every date in a range of a week.

var meetingdates = ['07/31/2013', '08/02/2013', '08/03/2013', '08/04/2013', '08/05/2013', '08/07/2013'];

The meetingdates array contains dates, where there are 1 or more meetings.

var meetings = ['1', '3', '2', '4', '1', '5']

The meetings array contains the number of the meetings on the dates from meetingdates.

I want to compare the dates array with the meetings array, if an entry from the meetingsarray exists in dates I want to put the number of the meetings which belongs to that date in a new array, if theres no match an 0 will be inserted:

So after comparing the meetingsarray with dates this will be the final result.

 meetingsPerDate =  ['1', '0', '3', '2', '4', '1', '0', '0'];

I tried solving this with the following for-loop:

if(dates[y] == meetingdates [y]){
    meetingsPerDate [y] = meetings [y];
    }else {
         meetingsPerDate[y] = 0;
          }  
     }

I know I will be missing some numbers because both of the arrays are not following the same pattern, but I really don't know how to solve this.

I hope I've explained my problem well, if not please let me know.

Any help is very appreciated,

Thanks!

Blender · Accepted Answer · 2013-07-30 23:37:56Z

1

Use an object instead of an array:

var meetings = {
    '07/31/2013': 1,
    '08/02/2013': 3,
    '08/03/2013': 2,
    '08/04/2013': 4,
    '08/05/2013': 1,
    '08/07/2013': 5
}

And then just add the new dates into it:

var date;

for (var i = 0; i < dates.length; i++) {
    date = dates[i];

    if (date in meetings) {
        meetings[date] += 1;
    } else {
        meetings[date] = 1;
    }
}

answered Jul 30, 2013 at 23:37

Blender

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1 Comment

Jef Over a year ago

Thanks for your input! But I managed to find the solution myself.

Jef · Accepted Answer · 2013-07-31 00:24:26Z

0

Not sure if it's the best solution. But I managed to find the answer to my problem:

for (var i = 0; i < dates.length; i++) {
    var arrayIndex = meetingdates.indexOf(dates[i]);

    if (arrayIndex == -1) {
        console.log(dates[i] + ' ' + 0);
    } else {
        console.log(dates[i] + ' ' + meetings[arrayIndex]);
  }

This small loop returns exactly what I needed.

answered Jul 31, 2013 at 0:24

Jef

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