python 反射

反射
getattr

通过字符串从指定对象获取的属性; getattr（x，'y'）相当于x.y.

# getattr(o,name) #通过字符串从指定对象获取的属性; getattr（x，'y'）相当于x.y.
# def getattr(object, name, default=None):  # known special case of getattr
"""
getattr(object, name[, default]) -> value

Get a named attribute from an object; getattr(x, 'y') is equivalent to x.y.
When a default argument is given, it is returned when the attribute doesn't
exist; without it, an exception is raised in that case.
"""

hasattr

返回对象是否具有给定名称的属性。这是通过调用getattr（obj，name）和捕获AttributeError来完成的。

# hasattr 返回对象是否具有给定名称的属性。这是通过调用getattr（obj，name）和捕获AttributeError来完成的。
# def hasattr(*args, **kwargs):  # real signature unknown
#     """
#     Return whether the object has an attribute with the given name.
#
#     This is done by calling getattr(obj, name) and catching AttributeError.
#     """
#     pass

setattr

将指定对象的命名属性设置为指定值。 setattr（x，'y'，v）相当于``x.y = v'' (动态添加)

# setattr 将指定对象的命名属性设置为指定值。 setattr（x，'y'，v）相当于``x.y = v'' (动态添加)
# def setattr(x, y, v):  # real signature unknown; restored from __doc__
#     """
#     Sets the named attribute on the given object to the specified value.
#
#     setattr(x, 'y', v) is equivalent to ``x.y = v''
#     """
#     pass

 

delattr   从给定对象中删除命名属性。delattr（x，'y'）相当于``del x.y'    （动态删除）

# delattr   从给定对象中删除命名属性。delattr（x，'y'）相当于``del x.y'    （动态删除）
# def delattr(x, y):  # real signature unknown; restored from __doc__
#     """
#     Deletes the named attribute from the given object.
#
#     delattr(x, 'y') is equivalent to ``del x.y''
#     """
#     pass

from prettytable import PrettyTable


class Course(object):
    def __init__(self, name, price, period):
        self.name = name
        self.price = price
        self.period = period


class Student(object):
    def __init__(self, name):
        self.name = name
        self.all_courses = None
        self.courses = []

    def select_course(self):
        course_id = input('请输入课程id:')
        if course_id.isdigit() and 0 < int(course_id) <= len(self.all_courses):
            course_id = int(course_id)
            choice_course = self.all_courses[course_id - 1]
            if choice_course not in self.courses:
                self.courses.append(choice_course)
                print('你选择的{} {}期课程已添加成功'.format(choice_course.name, choice_course.period))
            else:
                print('课程已存在，添加失败')
        else:
            print('输入有误，请重新输入！')

    def show_selected_course(self):
        course_table = PrettyTable(['ID', 'course_name', 'price', 'period'])
        for index, item in enumerate(self.courses, 1):
            c = [getattr(item, i) for i in item.__dict__]
            c.insert(0, index)
            course_table.add_row(c)
        print(course_table)

    def delete_course(self):
        print('请输入ID进行删除：')
        self.show_selected_course()
        choice = input('>>>')
        if choice.isdigit() and 0 < int(choice) <= len(self.courses):
            choice = int(choice)
            ret = self.courses.pop(choice - 1)
            print('你选择的{} {}期课程已删除成功！'.format(ret.name, ret.period))
        else:
            print('你的输入有误！')

    def show_all_course(self):
        info = PrettyTable(['id', 'course_name', 'price', 'period'])
        for index, item in enumerate(self.all_courses, 1):
            lst = [getattr(item, i) for i in item.__dict__]
            lst.insert(0, index)
            info.add_row(lst)
        print(info)


course_info = [('python', 10, 1), ('java', 20, 10),
               ('php', 30, 11), ('ruby', 10, 10),
               ('go', 10, 30), ('C', 30, 11), ('h5', 30, 10),
               ('C++', 10, 14), ('perl', 20, 10), ('C#', 30, 2)]


def run():
    """
    1.创建10个课程
    2.用户输入学生姓名，动态创建学生对象
    3.查看所有课程
    4.为学生选课
    5.查看学生已选课程
    6.删除已选课程
    """
    # 创建10课程
    features_list = ['select_course', 'show_selected_course', 'delete_course', 'show_all_course']
    all_course = [Course(*item) for item in course_info]
    student_name = input('请输入姓名:')
    student = Student(student_name)
    student.all_courses = all_course
    print('以下是所有课程信息,请按编号选择')
    student.show_all_course()
    while True:
        print('''1.选课
2.查看已选课程
3.删除已选课程
4.查看所有课程''')
        choice = input('请输入ID进行操作[q]:')
        if choice.upper() == 'Q':
            return
        if choice.isdigit() and 0 < int(choice) <= len(features_list):
            choice = int(choice)
            func = getattr(student, features_list[choice - 1])
            func()
        else:
            print('你的选择有误！')


run()