小编Dim*_*osh的帖子

我想创建这样的数组:

let arr = [0; length];

长度是a usize.但是我得到了这个错误

E0307
The length of an array is part of its type. For this reason, this length 
must be a compile-time constant.

是否可以创建动态长度的数组？我想要一个数组,而不是一个数组Vec.

在jinja我可以创建宏并在我的模板中调用它,如下所示:

{% macro create_list(some_list) %}
<ul>
    {% for item in some_list %}
    <li>{{ item }}</li>
    {% endfor %}
</ul>
{% endmacro %}

HTML code....

{{ create_list(list1) }}
{{ create_list(list2) }}
{{ create_list(list3) }}

我在django docs中读到django模板没有宏标签.我对在django模板中做这样的事情的最好方法感兴趣.

当我使用虚拟环境在Pycharm中启动一个新项目时,我得到了一个未解决的参考警告消息.

但是我已经在我的虚拟环境中安装了django,这段代码运行正常.

我怎样才能解决这个问题？我正在使用PyCharm 4.5.2 Pro

我想创建共享按钮，该按钮将使用 android ACTION_SEND 意图来共享图像。这是我的代码：

from kivy.setupconfig import USE_SDL2


def share(path):
    if platform == 'android':
        from jnius import cast
        from jnius import autoclass
        if USE_SDL2:
            PythonActivity = autoclass('org.kivy.android.PythonActivity')
        else:
            PythonActivity = autoclass('org.renpy.android.PythonActivity')
        Intent = autoclass('android.content.Intent')
        String = autoclass('java.lang.String')
        Uri = autoclass('android.net.Uri')
        File = autoclass('java.io.File')

        shareIntent = Intent(Intent.ACTION_SEND)
        shareIntent.setType('"image/*"')
        imageFile = File(path)
        uri = Uri.fromFile(imageFile)
        shareIntent.putExtra(Intent.EXTRA_STREAM, uri)

        currentActivity = cast('android.app.Activity', PythonActivity.mActivity)
        currentActivity.startActivity(shareIntent)

但它不起作用）它jnius.jnius.JavaException: Invalid instance of u'android/net/Uri' passed for a u'java/lang/String'在这一行中引发了这个错误shareIntent.putExtra(Intent.EXTRA_STREAM, uri)。我怎样才能解决这个问题？

我有2个型号:

from django.db import models

STATUSES = (
    ('f', 'Finished'),
)


class Battery(models.Model):
    energy = models.CharField(max_length=10)
    current = models.CharField(max_length=10)


class Charger(models.Model):
    status = models.CharField(max_length=1, choices=STATUSES)

我想创建序列化器,将这2个模型序列化在一起.我的serializers.py:

from rest_framework import serializers
from .models import Battery, Charger


class BatterySerializer(serializers.ModelSerializer):
    class Meta:
        model = Battery


class ChargerSerializer(serializers.ModelSerializer):
    status = serializers.SerializerMethodField()

    class Meta:
        model = Charger

    def get_status(self, obj):
        return obj.get_status_display()


class DeviceSerializer(serializers.Serializer):
    battery = BatterySerializer()
    charger = ChargerSerializer()
    some_field = serializers.CharField()

由于Charger模型在状态字段中有选择,因此我添加了SerializerMethodField以显示完整状态.然后我创建一个这样的视图:

class DeviceView(APIView):
    def get(self, request, format=None):
        battery = Battery.objects.get(id=1)
        charger = …

当我尝试运行此测试时：

from django.test import TestCase
from django.core.urlresolvers import reverse
from django.test import Client

class StatisticTest(TestCase):
    def setUp(self):
        self.client = Client()

    def test_schedule_view(self):
        url = reverse('schedule')
        response = self.client.get(url)
        self.assertEqual(response.status_code, 200)
        self.assertTemplateUsed(response, 'schedule.html')

我得到AssertionError：没有用于呈现响应的模板。

我的看法是：

class Schedule(View):
    def get(self, request):
        games = add_team_info(query.get_current_schedule())
        if games is not []:
             available_schedules = generate_schedule_list(games[0]["season_type"], games[0]["week"])
             is_available = True
        else:
             available_schedules = []
             is_available = False
        return render_to_response("schedule.html", 
                              {"games": games, "available_schedules": available_schedules, "is_available": is_available})

和urls.py：

url(r'^schedule/$', views.Schedule.as_view(), name='schedule'),

94％的Rust编译器是用Rust编写的。所以我不知道怎么可能？因为要编译rustc，您已经必须具有一些rust编译器。有人可以解释它的工作方式以及rust编译器的创建方式吗？

当我尝试使用pip安装matplotlib时，抛出异常：

In file included from /usr/include/numpy/ndarrayobject.h:26:0,
                 from src/file_compat.h:7,
                 from src/ft2font_wrapper.cpp:3:
/usr/include/numpy/__multiarray_api.h: In function ‘int _import_array()’:
/usr/include/numpy/__multiarray_api.h:1686:13: error: ‘NPY_CPU_UNKNOWN_ENDIAN’ was not declared in this scope
   if (st == NPY_CPU_UNKNOWN_ENDIAN) {
             ^
/usr/include/numpy/__multiarray_api.h:1697:13: error: ‘NPY_CPU_LITTLE’ was not declared in this scope
   if (st != NPY_CPU_LITTLE) {
             ^
error: command 'cc' failed with exit status 1

----------------------------------------
Command "/usr/bin/pypy -u -c "import setuptools, tokenize;__file__='/tmp/pip-build-vGxrsz/matplotlib/setup.py';exec(compile(getattr(tokenize, 'open', open)(__file__).read().replace('\r\n', '\n'), __file__, 'exec'))" install --record /tmp/pip-oB9gVW-record/install-record.txt --single-version-externally-managed --compile" failed with error code 1 in /tmp/pip-build-vGxrsz/matplotlib

如果我正确理解它的问题在numpy中。我使用以下命令安装它：

pypy …

如何覆盖bulk_create方法？我试试这个

class SomeModel(models.Model):
    field = models.CharField()

    def bulk_create(self, objs, batch_size=None):
        #do something
        return super(SomeModel, self).bulk_create(objs, batch_size)

但它不起作用.当我运行此代码时

SomeModel.objects.bulk_create(objects_list)

它创建了新对象,但它不使用我的覆盖bulk_create方法.是否可以覆盖bulk_create？如何？

嗨我的项目适用于Django和一些AngularJS.我想将我的Django模型字段值映射到一些自定义字符串值.以下是我的模型,

class History(models.Model):
    TYPE_CHOICES = (
        (1, 'CREATE'),
        (0, 'EDIT'),
        (2, 'DELETE'),
    )
    user = models.ForeignKey(User, related_name='+')
    mw = models.ForeignKey('CP', related_name="history")
    field_name = models.CharField(max_length=192, null=False)
    old_value = models.CharField(max_length=500, null=True, blank=True)
    new_value = models.CharField(max_length=500, null=True, blank=True)
    type = models.IntegerField(default=0, choices=TYPE_CHOICES)
    date_created = models.DateTimeField(auto_now_add=True)

我需要在我的网站上显示类型1,2和0.所以我只是将值传递<td>{{t.type}}</td>给它但是它给我的值为1,2和0.如何将其显示为创建,更新或删除字符串值？伙计们好吗？提前致谢.