count
Returns the number of elements in a set
Syntax
y = count[given]
y = count[given, per]
Attributes
given- the set to count overper- optional - one or more attributes by which to groupgiven.
Description
y = count[given] counts the number of elements in given.
y = count[given, per] counts the number of elements in given, grouped by the attribute(s) provided in per. For instance, class-size = count[given: students, per: grade] would count the number of students in each grade. You can group along multiple axes; the previous example could be extended to work across multiple schools by doing class-size = count[given: students, per: (grade, school)]. See the examples section to see these in action.
Examples
Before we get to the count examples, let’s add some students. Each #student has a grade and a school. Grades are one of 10, 11, or 12. Schools are one of “West” and “East”.
commit
[#student name: "Diedra" grade: 10 school: "West"]
[#student name: "Celia" grade: 10 school: "West"]
[#student name: "Michaela" grade: 11 school: "West"]
[#student name: "Jermaine" grade: 11 school: "West"]
[#student name: "Issac" grade: 12 school: "West"]
[#student name: "Jamar" grade: 12 school: "West"]
[#student name: "Yee" grade: 10 school: "East"]
[#student name: "Johanne" grade: 10 school: "East"]
[#student name: "Mertie" grade: 10 school: "East"]
[#student name: "Elmira" grade: 11 school: "East"]
First let’s count the total number of students in the school district.
search
students = [#student]
enrollment = count[given: students]
bind @view
[#value | value: "There are {{enrollment}} students in the district"]
Now let’s count the number of students in each school.
search
students = [#student school]
school-enrollment = count[given: students, per: school]
bind @view
[#value | value: "{{school-enrollment}} attend {{school}}"]
We could have similarly counted the number of students in each grade across the district.
search
students = [#student grade]
grade-enrollment = count[given: students, per: grade]
bind @view
[#value | value: "{{grade-enrollment}} students are in {{grade}}th grade"]
Finally, we can count the number of students per grade, per school.
search
students = [#student grade school]
grade-school-enrollment = count[given: students, per: (grade, school)]
bind @view
[#value | value: "{{grade-school-enrollment}} students are in {{grade}}th grade at {{school}}"]