Python Django中不规则嵌入阵列字段的处理

我目前正在将Django与PostgreSQL一起使用。我使用

django extensions

运行自定义脚本，将数据插入数据库。我有一个模型如下：

class Route(models.Model):
    """
    Bus routes of İzmir.
    """

    code = models.PositiveSmallIntegerField(
        unique=True,
        primary_key=True,
        verbose_name="Code"
    )

    stops = models.ManyToManyField(
        Stop,
        null=True,
        blank=True,
        related_name="routes",
        verbose_name="Stops"
    )

    terminals = ArrayField(
        models.CharField(
            null=False,
            blank=False,
            max_length=32,
        ),
        size=2,
        default=[],
        verbose_name="Terminals"
    )

    departure_times = ArrayField(
        ArrayField(
            models.TimeField(
                null=False,
                blank=False
            ),
            null=True, # This was added later to maybe solve the problem.
            default=[]
        ),
        default=[],
        size=6,
        verbose_name="Departure Times"
    )

    class Meta:
        verbose_name = "Route"
        verbose_name_plural = "Routes"
        ordering = ["code"]

[
    [1, 2, 3],
    [4, 5],
    [6, 7, 8, 9, 10]
]

def equalizer(data):
    largest_length = 0 # To define the largest length

    for l in data:
        if len(l) > largest_length:
            largest_length = len(l) # Will define the largest length in data.

    for i, l in enumerate(data):
        if len(l) < largest_length:
            remainder = largest_length - len(l) # Difference of length of particular list and largest length
            data[i].extend([None for i in range(remainder)]) # Add None through the largest length limit

    return data

如您所见，我已将另一个

数组字段

嵌入到

出发时间

。我的数据有不规则的形状，如注释中所述。因此，自然会产生如下错误：

class Route(models.Model):
    """
    Bus routes of İzmir.
    """

    code = models.PositiveSmallIntegerField(
        unique=True,
        primary_key=True,
        verbose_name="Code"
    )

    stops = models.ManyToManyField(
        Stop,
        null=True,
        blank=True,
        related_name="routes",
        verbose_name="Stops"
    )

    terminals = ArrayField(
        models.CharField(
            null=False,
            blank=False,
            max_length=32,
        ),
        size=2,
        default=[],
        verbose_name="Terminals"
    )

    departure_times = ArrayField(
        ArrayField(
            models.TimeField(
                null=False,
                blank=False
            ),
            null=True, # This was added later to maybe solve the problem.
            default=[]
        ),
        default=[],
        size=6,
        verbose_name="Departure Times"
    )

    class Meta:
        verbose_name = "Route"
        verbose_name_plural = "Routes"
        ordering = ["code"]

[
    [1, 2, 3],
    [4, 5],
    [6, 7, 8, 9, 10]
]

def equalizer(data):
    largest_length = 0 # To define the largest length

    for l in data:
        if len(l) > largest_length:
            largest_length = len(l) # Will define the largest length in data.

    for i, l in enumerate(data):
        if len(l) < largest_length:
            remainder = largest_length - len(l) # Difference of length of particular list and largest length
            data[i].extend([None for i in range(remainder)]) # Add None through the largest length limit

    return data

django.db.utils.DataError:多维数组必须具有具有匹配维度的数组表达式

正如文档中提到的“底层字段应设置为可空”，我将

null=True

添加到嵌入的

ArrayField

。但是，我不理解文件说明中的以下陈述：

值填充为“无”

我头上的问题是 1） 我是否会处理这些数据，修改不规则列表的长度，如下所示

[a, b, c, None, None]
[a, b, None, None, None]
[a, b, c, d, e]

2） 是否有一种内置的方法来克服

数据错误

---

如果您认为看到脚本可以帮助您解决问题

---

环境

• python 3.5.1
• django 1.9.7
• psycopg2 2.6.2
• postgresql 9.5

---

因此，似乎没有人参与这个问题。因此，我想分享我自己的解决方案。简言之，我以上述问题（1）的方式修改了脚本，这意味着，我使用filler

None

值扩展了每个列表，以均衡每个列表的长度
假设我有以下数据：

class Route(models.Model):
    """
    Bus routes of İzmir.
    """

    code = models.PositiveSmallIntegerField(
        unique=True,
        primary_key=True,
        verbose_name="Code"
    )

    stops = models.ManyToManyField(
        Stop,
        null=True,
        blank=True,
        related_name="routes",
        verbose_name="Stops"
    )

    terminals = ArrayField(
        models.CharField(
            null=False,
            blank=False,
            max_length=32,
        ),
        size=2,
        default=[],
        verbose_name="Terminals"
    )

    departure_times = ArrayField(
        ArrayField(
            models.TimeField(
                null=False,
                blank=False
            ),
            null=True, # This was added later to maybe solve the problem.
            default=[]
        ),
        default=[],
        size=6,
        verbose_name="Departure Times"
    )

    class Meta:
        verbose_name = "Route"
        verbose_name_plural = "Routes"
        ordering = ["code"]

[
    [1, 2, 3],
    [4, 5],
    [6, 7, 8, 9, 10]
]

def equalizer(data):
    largest_length = 0 # To define the largest length

    for l in data:
        if len(l) > largest_length:
            largest_length = len(l) # Will define the largest length in data.

    for i, l in enumerate(data):
        if len(l) < largest_length:
            remainder = largest_length - len(l) # Difference of length of particular list and largest length
            data[i].extend([None for i in range(remainder)]) # Add None through the largest length limit

    return data

期望输出为：

[
    [1, 2, 3, None, None],
    [4, 5, None, None, None],
    [6, 7, 8, 9, 10]
]

因此，我刚刚创建了一个示例函数，以备将来有人需要，如下所示：

class Route(models.Model):
    """
    Bus routes of İzmir.
    """

    code = models.PositiveSmallIntegerField(
        unique=True,
        primary_key=True,
        verbose_name="Code"
    )

    stops = models.ManyToManyField(
        Stop,
        null=True,
        blank=True,
        related_name="routes",
        verbose_name="Stops"
    )

    terminals = ArrayField(
        models.CharField(
            null=False,
            blank=False,
            max_length=32,
        ),
        size=2,
        default=[],
        verbose_name="Terminals"
    )

    departure_times = ArrayField(
        ArrayField(
            models.TimeField(
                null=False,
                blank=False
            ),
            null=True, # This was added later to maybe solve the problem.
            default=[]
        ),
        default=[],
        size=6,
        verbose_name="Departure Times"
    )

    class Meta:
        verbose_name = "Route"
        verbose_name_plural = "Routes"
        ordering = ["code"]

[
    [1, 2, 3],
    [4, 5],
    [6, 7, 8, 9, 10]
]

def equalizer(data):
    largest_length = 0 # To define the largest length

    for l in data:
        if len(l) > largest_length:
            largest_length = len(l) # Will define the largest length in data.

    for i, l in enumerate(data):
        if len(l) < largest_length:
            remainder = largest_length - len(l) # Difference of length of particular list and largest length
            data[i].extend([None for i in range(remainder)]) # Add None through the largest length limit

    return data

def均衡器（数据）： 最大长度=0#定义最大长度 对于l in数据： 如果长度（l）>最大长度： 最大长度=len（l）#将定义数据中的最大长度。 对于枚举中的i，l（数据）： 如果长度（l）<最大长度： 余数=最大长度-长度（l）#特定列表长度与最大长度之差 数据[i]。扩展（[i在范围内为无（剩余）]）#通过最大长度限制添加无 返回数据

---

这样就没有任何

DataError

可显示。如果没有更好的解决方案，此答案将在两天内被接受为有效。
感谢您分享您的解决方案，它确实帮助了我。然而，我相信我找到了一个更优雅的解决方案。他是我的看法：

    def save(self, *args, **kwargs):
         max_lenght = max(len(element) for element in self.NestedArrays)
         [[element.append(None) for _ in range(max_lenght - len(element))] for element in self.NestedArrays if len(element) != max_lenght]
         super(ParentClass, self).save(*args, **kwargs)  # Call the "real" save() method.

基本上我覆盖了默认的save方法。然后修改NestedArrays属性并最终保存它。此方法将添加到存在此问题的模型类中。在这种情况下，我称之为父类
有关重写模型方法的详细信息
希望这对别人有帮助