老师 为什么使用data['count']返回的结果是这样的

使用data.count返回的结果是这样的呢？

    老师可以给一下画UML图的软件吗   

'''
说明：
1、为了节省类视图转换为函数视图的次数，所以把转换方法写在了父类，
2、为了父类return能够用jsonify处理数据，所以父类必须存在一个getDate的方法(空的也可以)，这样才能使用self.getData()
3、为了子类能够处理不同的数据，所以必须重写getDate方法，才能用jsonify处理来源不同的数据
'''

安装flask-restful报错

命令：pip install flask-restful

ERROR: Could not find a version that satisfies the requirement pytz (from flask-restful) (from versions: none)

ERROR: No matching distribution found for pytz (from flask-restful)

from django.db import models

# Create your models here.
class Question(models.Model):
    question_text = models.CharField(max_length=200)
    pub_date = models.DateTimeField()

上面是orm类

下面是python manage.py makemigrations mosel_app创建得0001

# Generated by Django 2.2.6 on 2019-10-25 02:46

from django.db import migrations, models


class Migration(migrations.Migration):

    initial = True

    dependencies = [
    ]

    operations = [
        migrations.CreateModel(
            name='Question',
            fields=[
                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
                ('question_text', models.CharField(max_length=200)),
                ('pub_date', models.DateTimeField()),
            ],
        ),
    ]

但是在cmd运行python manage.py migrate  出现下面错误

Operations to perform:

  Apply all migrations: admin, auth, contenttypes, model_app, sessions

Running migrations:

Traceback (most recent call last):

  File "D:\python_virtualEnv\django_env\lib\site-packages\django\db\backends\utils.py", line 82, in _execute

    return self.cursor.execute(sql)

  File "D:\python_virtualEnv\django_env\lib\site-packages\django\db\backends\mysql\base.py", line 71, in execute

    return self.cursor.execute(query, args)

  File "D:\python_virtualEnv\django_env\lib\site-packages\MySQLdb\cursors.py", line 209, in execute

    res = self._query(query)

  File "D:\python_virtualEnv\django_env\lib\site-packages\MySQLdb\cursors.py", line 315, in _query

    db.query(q)

  File "D:\python_virtualEnv\django_env\lib\site-packages\MySQLdb\connections.py", line 226, in query

    _mysql.connection.query(self, query)

MySQLdb._exceptions.ProgrammingError: (1064, "You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '(6) NOT NULL)' at line 1")

The above exception was the direct cause of the following exception:

Traceback (most recent call last):

  File "D:\python_virtualEnv\django_env\lib\site-packages\django\db\migrations\recorder.py", line 67, in ensure_schema

    editor.create_model(self.Migration)

  File "D:\python_virtualEnv\django_env\lib\site-packages\django\db\backends\base\schema.py", line 307, in create_model

    self.execute(sql, params or None)

  File "D:\python_virtualEnv\django_env\lib\site-packages\django\db\backends\base\schema.py", line 137, in execute

    cursor.execute(sql, params)

  File "D:\python_virtualEnv\django_env\lib\site-packages\django\db\backends\utils.py", line 99, in execute

    return super().execute(sql, params)

  File "D:\python_virtualEnv\django_env\lib\site-packages\django\db\backends\utils.py", line 67, in execute

    return self._execute_with_wrappers(sql, params, many=False, executor=self._execute)

  File "D:\python_virtualEnv\django_env\lib\site-packages\django\db\backends\utils.py", line 76, in _execute_with_wrappers

    return executor(sql, params, many, context)

  File "D:\python_virtualEnv\django_env\lib\site-packages\django\db\backends\utils.py", line 84, in _execute

    return self.cursor.execute(sql, params)

  File "D:\python_virtualEnv\django_env\lib\site-packages\django\db\utils.py", line 89, in __exit__

    raise dj_exc_value.with_traceback(traceback) from exc_value

  File "D:\python_virtualEnv\django_env\lib\site-packages\django\db\backends\utils.py", line 82, in _execute

    return self.cursor.execute(sql)

  File "D:\python_virtualEnv\django_env\lib\site-packages\django\db\backends\mysql\base.py", line 71, in execute

    return self.cursor.execute(query, args)

  File "D:\python_virtualEnv\django_env\lib\site-packages\MySQLdb\cursors.py", line 209, in execute

    res = self._query(query)

  File "D:\python_virtualEnv\django_env\lib\site-packages\MySQLdb\cursors.py", line 315, in _query

    db.query(q)

  File "D:\python_virtualEnv\django_env\lib\site-packages\MySQLdb\connections.py", line 226, in query

    _mysql.connection.query(self, query)

django.db.utils.ProgrammingError: (1064, "You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '(6) NOT NULL)' at line 1")

During handling of the above exception, another exception occurred:

Traceback (most recent call last):

  File "manage.py", line 21, in <module>

    main()

  File "manage.py", line 17, in main

    execute_from_command_line(sys.argv)

  File "D:\python_virtualEnv\django_env\lib\site-packages\django\core\management\__init__.py", line 381, in execute_from_command_line

    utility.execute()

  File "D:\python_virtualEnv\django_env\lib\site-packages\django\core\management\__init__.py", line 375, in execute

    self.fetch_command(subcommand).run_from_argv(self.argv)

  File "D:\python_virtualEnv\django_env\lib\site-packages\django\core\management\base.py", line 323, in run_from_argv

    self.execute(*args, **cmd_options)

  File "D:\python_virtualEnv\django_env\lib\site-packages\django\core\management\base.py", line 364, in execute

    output = self.handle(*args, **options)

  File "D:\python_virtualEnv\django_env\lib\site-packages\django\core\management\base.py", line 83, in wrapped

    res = handle_func(*args, **kwargs)

  File "D:\python_virtualEnv\django_env\lib\site-packages\django\core\management\commands\migrate.py", line 234, in handle

    fake_initial=fake_initial,

  File "D:\python_virtualEnv\django_env\lib\site-packages\django\db\migrations\executor.py", line 91, in migrate

    self.recorder.ensure_schema()

  File "D:\python_virtualEnv\django_env\lib\site-packages\django\db\migrations\recorder.py", line 69, in ensure_schema

    raise MigrationSchemaMissing("Unable to create the django_migrations table (%s)" % exc)

django.db.migrations.exceptions.MigrationSchemaMissing: Unable to create the django_migrations table ((1064, "You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '(6) NOT NULL)' at line 1"))

提示我一个语法错误，什么NOT NULL，这是什么意思？？？

按需导入出现问题

这几集的笔记和资料能不能补发一下下下下？

老师说的 textarea 标签获取其内容，发现只有 innerText 不好使，但是使用 innerHTML 是可以获得内容的呢

[class]和[ngClass]效果不是一样的吗？

什么时候该用用throws抛出异常，什么时候该用try-catch，我感觉try-catch处理异常不是很明白，throws感觉很方便，两者区别是什么

如果用的是阿里云的服务器，也是和这个一样的安装步骤吗？

struct
math
threading
time
sys
multiprocessing
multiprocessing Process


read_csv(filename):

    start_time = time.time()

    sem
    sem = threading.Semaphore()

    file
    file = (filename, )
    (% file.read().decode())

    encoded_triangles = file.read()
    triangles = .from_bytes(encoded_triangles, )

    manager = multiprocessing.Manager()
    return_tot = manager.dict()
    totals = []

    return_coord = manager.dict()
    coords = []


    index (, ):
        p = Process(=thread_compute, =(index, triangles, return_tot, return_coord))
        totals.append(p)
        coords.append(p)
        p.start()
    
    index (, ):
        p.join()

    total_area = index (, ):
        total_area += return_tot[index]

    min_box = find_box(return_coord[], return_coord[], return_coord[], return_coord[])

    end_time = time.time()
    total_time = end_time - start_time

    triangles, total_area, min_box, total_time

thread_compute(index, triangles, return_tot, return_coord):
    total_area = min_max = []

    start = (index * triangles / )
    (triangles / )  > triangles - :
        end = triangles
    :
        end = start + (triangles / )

    triangle (start, end):
        
        sem.acquire()
        = [file.read(), file.read(), file.read()]
        p1 = [file.read(), file.read(), file.read()]
        p2 = [file.read(), file.read(), file.read()]
        p3 = [file.read(), file.read(), file.read()]
        = file.read()
        sem.release()

        p1, p2, p3 = process_coord(p1, p2, p3)
        tri_area = compute(p1, p2, p3)

        total_area += tri_area

        temp = []
        i (,):
            temp.append(([p1[i], p2[i], p3[i]]))
        i (,):
            temp.append(([p1[i], p2[i], p3[i]]))

        triangle == start:
            min_max = temp
        :
            i (,):
                temp[i] < min_max[i]:
                    min_max[i] = temp[i]
            i (,):
                temp[i] > min_max[i]:
                    min_max[i] = temp[i]

    return_coord[index] = min_max
    return_tot[index] = total_area

process_coord(p1, p2, p3):
    p1 = convert_values(p1)
    p2 = convert_values(p2)
    p3 = convert_values(p3)
    p1, p2, p3

convert_values(point):
    [struct.unpack(, point[])[],
            struct.unpack(, point[])[],
            struct.unpack(, point[])[]]

compute(p1, p2, p3):
    a = math.sqrt((p2[] - p1[]) ** + (p2[] - p1[]) ** + (p2[] - p1[]) ** )
    b = math.sqrt((p3[] - p1[]) ** + (p3[] - p1[]) ** + (p3[] - p1[]) ** )
    c = math.sqrt((p3[] - p2[]) ** + (p3[] - p2[]) ** + (p3[] - p2[]) ** )
    p = (a + b + c) / area = math.sqrt(p * (p - a) * (p - b) * (p - c))
    area

find_box(min_max1, min_max2, min_max3, min_max4):

    = []
    min_max = min_max1

    i (,):
        min_max2[i] < min_max[i]:
            min_max[i] = min_max2[i]
    i (,):
        min_max2[i] > min_max[i]:
            min_max[i] = min_max2[i]
    i (,):
        min_max3[i] < min_max[i]:
            min_max[i] = min_max3[i]
    i (,):
        min_max3[i] > min_max[i]:
            min_max[i] = min_max3[i]
    i (,):
        min_max4[i] < min_max[i]:
            min_max[i] = min_max4[i]
    i (,):
        min_max4[i] > min_max[i]:
            min_max[i] = min_max4[i]
    
    
    line1 = math.sqrt((min_max[] - min_max[]) ** )
    line2 = math.sqrt((min_max[] - min_max[]) ** )
    line3 = math.sqrt((min_max[] - min_max[]) ** )
    box = % (line1, line2, line3)
    box

show_output(triangles, total_area, min_box, ):
    (% triangles)
    (% total_area)
    (% min_box)
    (% )

__name__ == :
    (sys.argv) < :
        ()
    filename = (sys.argv[])
    triangles, total_area, min_box, total_time = read_csv(filename)
    show_output(triangles, total_area, min_box, total_time)

老师，您帮我看看，这个报这个错误，我应该在哪里输入文件名字