1
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Maybe I'm not interested in the scores, I just want to know how many exams friend here took. This is also something

2
00:00:11,360 --> 00:00:13,620
you can easily find out in the project

3
00:00:13,620 --> 00:00:17,040
phase, you could add some scores here

4
00:00:17,340 --> 00:00:26,030
and then we can use a helpful operator, the size operator which calculates the length of an array.

5
00:00:26,130 --> 00:00:33,300
And here we can simply input the well name of the field which holds the array or again hardcode an

6
00:00:33,300 --> 00:00:35,810
array in here if you wanted to, for whatever reason.

7
00:00:36,060 --> 00:00:41,800
So here I will point at exam scores and I will calculate the size for that array and store it in

8
00:00:41,800 --> 00:00:43,380
num scores.

9
00:00:43,380 --> 00:00:46,440
So if I now copy that entire command here,

10
00:00:49,710 --> 00:00:56,400
you see we get three for every user because every user happens to have three exams in our dataset here

11
00:00:56,440 --> 00:01:03,760
but this is how you can get the length of an array, with $size operator and then a pointer

12
00:01:03,910 --> 00:01:07,130
to the field which holds the array for which you want to calculate the length

13
00:01:07,210 --> 00:01:09,370
and then this gets stored in a new field.