Algosim documentation: member

member

Accesses a given member of a given structure, or creates a function that accesses a given member of its argument.

Syntax

Description

If S is a structure and s a string, then member(S, s) returns the value of the member named s in S.

If s is a string, then member(s) returns the function S ↦ member(S, s).

Examples

person ≔ (fn, ln, role) ↦ struct("FirstName": fn, "LastName": ln, "role": role);
L ≔ '(person("Albus", "Dumbledore", "headmaster"), person("Minerva", "McGonagall", "teacher"), person("Severus", "Snape", "teacher"), person("Pomona", "Sprout", "teacher"), person("Filius", "Flitwick", "teacher"), person("Horace", "Slughorn", "teacher"), person("Harry", "Potter", "student"), person("Ronald", "Weasley", "student"), person("Hermione", "Granger", "student"), person("Remus", "Lupin", "teacher"), person("Rubeus", "Hagrid", "teacher"), person("Luna", "Lovegood", "student"))

(FirstName: Albus, LastName: Dumbledore, role: headmaster)
(FirstName: Minerva, LastName: McGonagall, role: teacher)
(FirstName: Severus, LastName: Snape, role: teacher)
(FirstName: Pomona, LastName: Sprout, role: teacher)
(FirstName: Filius, LastName: Flitwick, role: teacher)
(FirstName: Horace, LastName: Slughorn, role: teacher)
(FirstName: Harry, LastName: Potter, role: student)
(FirstName: Ronald, LastName: Weasley, role: student)
(FirstName: Hermione, LastName: Granger, role: student)
(FirstName: Remus, LastName: Lupin, role: teacher)
(FirstName: Rubeus, LastName: Hagrid, role: teacher)
(FirstName: Luna, LastName: Lovegood, role: student)

frequencies(L @ member("role"))
(headmaster, 1)
(teacher, 7)
(student, 4)

SortBy(L, member("LastName"))
(FirstName: Albus, LastName: Dumbledore, role: headmaster)
(FirstName: Filius, LastName: Flitwick, role: teacher)
(FirstName: Hermione, LastName: Granger, role: student)
(FirstName: Rubeus, LastName: Hagrid, role: teacher)
(FirstName: Luna, LastName: Lovegood, role: student)
(FirstName: Remus, LastName: Lupin, role: teacher)
(FirstName: Minerva, LastName: McGonagall, role: teacher)
(FirstName: Harry, LastName: Potter, role: student)
(FirstName: Horace, LastName: Slughorn, role: teacher)
(FirstName: Severus, LastName: Snape, role: teacher)
(FirstName: Pomona, LastName: Sprout, role: teacher)
(FirstName: Ronald, LastName: Weasley, role: student)

ApplyIf(GroupBy(L, member("role"), "role"), IsStructure, member("LastName"), 3)
(role: headmaster, members: (Dumbledore))
(role: student, members: (Weasley, Granger, Potter, Lovegood))
(role: teacher, members: (Lupin, Hagrid, McGonagall, Snape, Sprout, Flitwick, Slughorn))

See also