Listar por Curso

Parte da seção Lógica e fluxo do Journey de GDScript da Coddy. Lição 47 de 78.

Desafio

Fácil

Liste os estudantes que fazem um curso. Mantenha tudo o que você escreveu nas etapas anteriores.

1. A função. Abaixo das outras funções, escreva list_students_by_course(course: String) -> Array. Ela percorre student_records e retorna um array com os nomes dos estudantes cujo conjunto "courses" contém o curso, na ordem em que os estudantes foram adicionados. Quando ninguém faz o curso, ela retorna um array vazio.

2. O comando. Adicione um ramo para course <course>, como course Math, acima de ["show"]. Ele imprime o array retornado por list_students_by_course(). Para os comandos

add Alice 20 Math Physics
add Bob 22 Math Biology
add Diana 23 Chemistry Physics
course Math
course Physics
course Biology
course History
exit

a saída é:

Student 'Alice' added successfully.
Student 'Bob' added successfully.
Student 'Diana' added successfully.
["Alice", "Bob"]
["Alice", "Diana"]
["Bob"]
[]
Goodbye!

Experimente você mesmo

extends Node

# Cada estudante: nome -> {"age": int, "grades": Array, "courses": um conjunto de nomes de cursos}
var student_records := {}

func _ready():
	while true:
		var parts := Array(OS.read_string_from_stdin().split(" ", false))
		match parts:
			["add", var student, var age, ..]:
				add_student(student, int(age), parts.slice(3))
			["grade", var student, var grade]:
				add_grade(student, int(grade))
			["enrolled", var student, var course]:
				print(is_enrolled(student, course))
			["average", var student]:
				var average := calculate_average_grade(student)
				if average >= 0:
					print("Average grade of '%s': %.2f" % [student, average])
			["show"]:
				print(student_records)
			["exit"]:
				print("Goodbye!")
				break

func add_student(student_name: String, age: int, courses: Array) -> void:
	if student_records.has(student_name):
		print("Student '%s' already exists." % student_name)
		return
	var course_set := {}
	for course in courses:
		course_set[course] = true
	student_records[student_name] = {"age": age, "grades": [], "courses": course_set}
	print("Student '%s' added successfully." % student_name)

func add_grade(student_name: String, grade: int) -> void:
	if not student_records.has(student_name):
		print("Student '%s' not found." % student_name)
		return
	student_records[student_name]["grades"].append(grade)
	print("Grade %d added for student '%s'." % [grade, student_name])

func is_enrolled(student_name: String, course: String) -> bool:
	if not student_records.has(student_name):
		print("Student '%s' not found." % student_name)
		return false
	return student_records[student_name]["courses"].has(course)

func calculate_average_grade(student_name: String) -> float:
	if not student_records.has(student_name):
		print("Student '%s' not found." % student_name)
		return -1.0
	var grades: Array = student_records[student_name]["grades"]
	if grades.is_empty():
		return 0.0
	var total := 0
	for grade in grades:
		total += grade
	return float(total) / grades.size()