count

returns the total number of datapoints in the stream

Count represents the total number of datapoints passed through the transform. It is equivalent to an i used in a loop over an array, with the difference that count starts from 1, rather than 0.

No matter what the datapoints, the sequence of data that count returns is:

1,2,3,4,5...

Usage

Counting Mood

Suppose you want to count the number of times you were in a great mood:

filter $ >= 8 | count

The above transform will return only the datapoints where your mood rating was 8 or above, it will count them, and only return the last datapoint (which contains the full count).

Counting Visits

Suppose you want to find how many times you visited a friend:

distance(<latitude>,<longitude>) < 50 | filter changed | filter $ | count

The above transform finds when you were within 50 meters of the given coordinates (your friend’s home), filters these datapoints so only changes remain (so each time you visit, you get one true, followed by a false when you leave), filter the false values, and count the number of times you visited. Note that filter $ | count can be replaced with sum in this case.

Counting Weekdays

Now you want to see which weekdays you use your computer the most. You can simply count the datapoints in your laptop’s stream to see what days have most data:

map(weekday,count)

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Transform Details

Input Schema	Output Schema
{}	{ "type": "number" }