断言
断言的功能–assert
- 用于判断一个表达式，在
表达式条件为false的时候触发异常
用法
assert expression, message
参数
expression:表达式，一般是判断相等，或者判断是某种数据类型的bool判断的语句message:具体的错误信息
返回值
代码（学生信息库升级）
代码语言：javascript
复制# coding:utf-8
"""
学生信息库
"""
class NotArgError(Exception):
def __init__(self, message):
self.message = message
class StudentInfo(object):
def __init__(self, students):
self.students = students
def get_by_id(self, student_id):
return self.students.get(student_id)
def get_all_students(self):
for id_, value in self.students.items():
print('学号: {},姓名{},年龄{},性别{},班级{}'.format(
id_, value['name'], value['age'], value['sex'], value['class_number']
))
return self.students
def add(self, **student):
try:
self.check_user_info(**student)
except Exception as e:
raise e
self.__add(**student)
def adds(self, new_students):
for student in new_students:
try:
self.check_user_info(**student)
except Exception as e:
print(e, student.get('name'))
continue
self.__add(**student)
def __add(self, **student):
new_id = max(self.students) 1
self.students[new_id] = student
def delete(self, student_id):
if student_id not in self.students:
print('{}并不存在'.format(student_id))
else:
user_info = self.students.pop(student_id)
print('学号是{}, {}同学的信息已经被删除了'.format(student_id, user_info['name']))
def deletes(self, ids):
for id_ in ids:
if id_ not in self.students:
print(f'{id_}不存在学生库中')
continue
student_info = self.students.pop(id_)
print(f'学号{id_} 学生{student_info["name"]} 已被移除')
def update(self, student_id, **kwargs):
if student_id not in self.students:
print('并不存在这个学号:{}'.format(student_id))
try:
self.check_user_info(**kwargs)
except Exception as e:
raise e
self.students[student_id] = kwargs
print('同学信息更新完毕')
def updates(self, update_students):
for student in update_students:
try:
id_ = list(student.keys())[0]
except IndexError as e:
print(e)
continue
if id_ not in self.students:
print(f'学号{id_}不存在')
continue
user_info = student[id_]
try:
check = self.check_user_info(**user_info)
except Exception as e:
print(e)
continue
self.students[id_] = user_info
print('所有用户信息更新完成')
def search_users(self, **kwargs):
assert len(kwargs) == 1, '参数数量传递错误'
values = list(self.students.values())
key = None
value = None
result = []
if 'name' in kwargs:
key = 'name'
value = kwargs[key]
elif 'sex' in kwargs:
key = 'sex'
value = kwargs['sex']
elif 'class_number' in kwargs:
key = 'class_number'
value = kwargs[key]
elif 'age' in kwargs:
key = 'age'
value = kwargs[key]
else:
raise NotArgError('没有发现搜索的关键字')
for user in values: # [{name, sex, age, class_number}, {}]
# print(user[key])
# print(value)
if value in user[key]:
result.append(user)
return result
def check_user_info(self, **kwargs):
assert len(kwargs) == 4, '参数必须是4个'
if 'name' not in kwargs:
raise NotArgError('没有发现学生姓名参数')
if 'age' not in kwargs:
raise NotArgError('缺少学生年龄参数')
if 'sex' not in kwargs:
raise NotArgError('缺少学生性别参数')
if 'class_number' not in kwargs:
raise NotArgError('缺少学生班级参数')
name_value = kwargs['name'] # type(name_value)
age_value = kwargs['age']
sex_value = kwargs['sex']
class_number_value = kwargs['class_number']
# isinstance(对比的数据，目标类型） isinstance(1, str)
if not isinstance(name_value, str):
raise TypeError('name应该是字符串类型')
if not isinstance(age_value, int):
raise TypeError('age应该是整形')
if not isinstance(sex_value, str):
raise TypeError('sex应该是字符串类型')
if not isinstance(class_number_value, str):
raise TypeError('class_number应该是字符串类型')
students = {
1: {
'name': 'dewei',
'age': 33,
'class_number': 'A',
'sex': 'boy'
},
2: {
'name': '小慕',
'age': 10,
'class_number': 'B',
'sex': 'boy'
},
3: {
'name': '小曼',
'age': 18,
'class_number': 'A',
'sex': 'girl'
},
4: {
'name': '小高',
'age': 18,
'class_number': 'C',
'sex': 'boy'
},
5: {
'name': '小云',
'age': 18,
'class_number': 'B',
'sex': 'girl'
}
}
if __name__ == '__main__':
students_info = StudentInfo(students)
user = students_info.get_by_id(1)
students_info.add(name='dewei', age=34, class_number='A', sex='boy')
# print(students_info.students)
users = [
{'name': 'xiaoming', 'age': 17, 'class_number': 'b', 'sex': 'boy'},
{'name': 'xiaohong', 'age': 18, 'class_number': 'c', 'sex': 'girl'}
]
students_info.adds(users)
students_info.get_all_students()
print('-----------------')
students_info.deletes([7, 8])
students_info.get_all_students()
print('-------------')
students_info.updates([
{1: {'name': 'dewei.zhang', 'age': 18, 'class_number': 'A', 'sex': 'boy'}},
{2: {'name': '小慕同学', 'age': 18, 'class_number': 'A', 'sex': 'boy'}}
])
students_info.get_all_students()
result = students_info.search_users(name='d')
print(result)
result = students_info.search_users(name='小')
print(result)
# 如果同学想用年龄字段模糊查询,
# 需要把年龄改为str类型
print('---------------')
result = students_info.search_users(name='')
print(result)
