有一个班4个学生，5门课。 （1）.求第一门课的平均分； （2）.找出有两门以上课程不及格的学生， 输出他们的姓名、全部课程成绩及平均成绩； （3）.找出平均成绩在90分以上或全部课程成绩在 85分以上的学生。分别编3个函数实现以上3个要求。

为了满足上述需求，我们可以创建一个简单的Python类`Student`来表示每个学生，以及一个包含所有学生信息的`Class`类。以下是三个函数的实现：

class Student:
    def __init__(self, name):
        self.name = name
        self.grades = {i: None for i in range(1, 6)}

    def set_grade(self, course, grade):
        if 1 <= course <= 5:
            self.grades[course] = grade

    def get_average_grade(self):
        total = sum(self.grades.values())
        return total / len(self.grades) if total != 0 else 0


class Class:
    def __init__(self):
        self.students = []

    def add_student(self, name):
        student = Student(name)
        self.students.append(student)

    def average_grade_of_course_1(self):
        total_grades = [student.grades[1] for student in self.students if student.grades[1]]
        return sum(total_grades) / len(total_grades) if total_grades else "No grades available"

    def students_with_two_or_more_fails(self):
        result = []
        for student in self.students:
            fails = [grade for grade in student.grades.values() if grade < 60]
            if len(fails) >= 2:
                avg_grade = student.get_average_grade()
                result.append((student.name, student.grades, avg_grade))
        return result

    def high_average_students(self):
        high_scores = [student for student in self.students if student.get_average_grade() >= 90 or all(grade >= 85 for grade in student.grades.values())]
        return [student.name for student in high_scores]

# 使用示例
class_instance = Class()
class_instance.add_student("Alice")
class_instance.add_student("Bob")
class_instance.add_student("Charlie")
class_instance.add_student("Dave")

# ... 分别设置学生的成绩 ...

average_course1 = class_instance.average_grade_of_course_1()
students_with_fails = class_instance.students_with_two_or_more_fails()
high_score_students = class_instance.high_average_students()

print(f"First Course Average: {average_course1}")
print("Students with two or more failures:")
for student_info in students_with_fails:
    print(student_info)
print("High score students:", high_score_students)

这个代码首先定义了`Student`和`Class`类，然后创建了一个班级实例并添加了学生。之后，通过调用相应的函数获取所需的统计信息。