用Python实现一个Johnson变换的代码，输入一个列表list_x，输出转化后的列表list_y。

def Johnson_transform(list_x):
list_y = []
for i in range(len(list_x)):
list_y.append((list_x[i] + np.sqrt(list_x[i]**2 + 4))/2)
return list_y

相关问题

python读取list写入csv

可以使用Python内置的csv模块来将列表写入CSV文件。下面是一个示例代码：

import csv

# 一个包含数据的列表
data = [
    ['John', 'Doe', '123 Main St.'],
    ['Jane', 'Smith', '456 Broadway Ave.'],
    ['Bob', 'Johnson', '789 Market St.']
]

# 打开CSV文件进行写入
with open('output.csv', mode='w', newline='') as file:
    # 创建一个CSV写入器
    writer = csv.writer(file)
    
    # 将数据写入CSV文件
    writer.writerows(data)

这将会创建一个名为`output.csv`的文件，并将列表`data`写入其中。请注意，CSV写入器的`writerows`方法可以一次性写入多行数据。如果需要写入单行数据，可以使用`writer.writerow()`方法。

如何用python实现简单的学生选课系统

以下是一个简单的学生选课系统的 Python 代码示例：

class Student:
    def __init__(self, name, id_num):
        self.name = name
        self.id_num = id_num
        self.courses = []

    def add_course(self, course):
        self.courses.append(course)

    def remove_course(self, course):
        self.courses.remove(course)

class Course:
    def __init__(self, name, id_num, professor):
        self.name = name
        self.id_num = id_num
        self.professor = professor
        self.students = []

    def add_student(self, student):
        self.students.append(student)
        student.add_course(self)

    def remove_student(self, student):
        self.students.remove(student)
        student.remove_course(self)

    def list_students(self):
        for student in self.students:
            print(student.name)

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

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

    def add_course(self, name, id_num, professor):
        course = Course(name, id_num, professor)
        self.courses.append(course)

    def register_student(self, student_id, course_id):
        student = self.get_student_by_id(student_id)
        course = self.get_course_by_id(course_id)
        course.add_student(student)

    def unregister_student(self, student_id, course_id):
        student = self.get_student_by_id(student_id)
        course = self.get_course_by_id(course_id)
        course.remove_student(student)

    def list_students_in_course(self, course_id):
        course = self.get_course_by_id(course_id)
        course.list_students()

    def get_student_by_id(self, student_id):
        for student in self.students:
            if student.id_num == student_id:
                return student
        return None

    def get_course_by_id(self, course_id):
        for course in self.courses:
            if course.id_num == course_id:
                return course
        return None

# Example usage
school = School()
school.add_student("Alice", 1234)
school.add_student("Bob", 5678)
school.add_course("Math", 1001, "Prof. Smith")
school.add_course("Science", 1002, "Prof. Johnson")
school.register_student(1234, 1001)
school.register_student(5678, 1001)
school.register_student(5678, 1002)
school.list_students_in_course(1001)

这个简单的学生选课系统包括三个类：`Student`，`Course`和`School`。`Student`类表示学生，`Course`类表示课程，`School`类表示学校。在`School`类中，有一些方法可以添加学生和课程，注册学生到课程中，取消学生在课程中的注册，列出某个课程中的所有学生等。