How to convert nthWeek and nthMonth to date? - google-analytics-api

Question

I am trying to get weekly and monthly visitor totals with Google Analytics API for the last X years. I set:
metrics=ga:visitors
dimensions=ga:nthWeek (or nthMonth)
It returns the data I want:
0 week : 100 visitors
1 week : 200 visitors
2 week : 300 visitors
Only instead of week 0 I want it to be displayed as 01/01/2012. How do I convert Nth week (or month) to date?
I tried:
Passing ga:date as metrics (which would be a logical thing to do, similar to how it's done in SQL), but it doesn't recognize it as a valid metrics.
Passing ga:date as the second dimension prevents weekly grouping.

Answer 1

You don't mention what language you're using, so I don't know what sort of date-wrangling interfaces you have available to you, but ga:week,ga:year should provide you with the week of the year that you can plug in and allow you to build the date appropropriately. In PHP it might be something like the following:
<?php
// assuming use of the official PHP API for Google services, and
// that you've appropriately initialized the connection, and that
// you've chosen to "$client->setUserObjects(true)", and that you've
// initialized the necessary variables...
$results = $service->data_ga->get($analytics_id, $start_date, $end_date, 'ga:visitors',
array('dimensions' => 'ga:week,ga:nthWeek,ga:year'));
$columns = array();
foreach ($results->columnHeaders as $headidx => $col) {
$columns[$col->name] = $headidx;
}
$traffic = array();
foreach ($results->rows as $idx => $week) {
$date = new DateTime;
$date->setISODate($week[$columns['ga:year']], $week[$columns['ga:week']]);
$traffic[$week[$columns['ga:nthWeek']]] = array('date' => $date, 'visitors' => $week[$columns['ga:visitors']], 'visits' => $week[$columns['ga:visits']], 'pageviews' => $week[$columns['ga:pageviews']]);
}
ksort($traffic);
// $traffic now holds a sorted array of your week by week traffic, with the full
// date in the DateTime object that you can access and format however you please
?>