使用 Django 进行数据挖掘时出现问题
我已经建立了一个 Django 项目，在其中创建随机点。这些随机点存储在数据库（sqlite）中（我可以通过管理网站查看它们并更改值，所以这有效）。 如果我编写一个脚本，我可以访问这些点并将它们打印在图中。请参阅下面的代码。
但是，如果我想挖掘这些点来对它们进行排序或仅绘制数据集的选择，我似乎会遇到麻烦。如果我读出这些值，它们就不再连接，并且对 x 进行排序会混淆点集。 有没有办法将数据集排序为最小值（在本例中为 X）并对值进行排序并打印该集？ （保持点的所有 x、y、z 和名称值不变？）（参见下面的答案，point in Point3D.objects.all().order_by('x'):）
如果我现在想要 x 的值介于 x = 12 和 x = 30 之间？我如何添加这个额外的过滤器？
我的代码如下： models.py：
class Point3D(models.Model):
name = models.CharField(max_length = 10)
x = models.DecimalField(max_digits=5, decimal_places=2)
y = models.DecimalField(max_digits=5, decimal_places=2)
z = models.DecimalField(max_digits=5, decimal_places=2)
生成点：
from books.models import Point3D
def points():
for i in range(20):
x = random.randint(0,100)
y = random.randint(0,100)
z = random.randint(0,100)
p = Point3D(name = x , x = x ,y = y,z = z)
# print 'test'
p.save()
#
points()
在views.py中：
def ThreeGraphs(request):
fig = Figure()
fig.suptitle('2D-punten')
ax = fig.add_subplot(111)
for point in Point3D.objects.all():
print point
name = int(point.name)
xs = int(point.x)
ys = int(point.y)
zs = int(point.z)
print (xs, ys, zs)
ax.plot(xs, ys, 'bo' )
HttpResponse(mimetype="image/png")
FigureCanvas(fig)
fig.savefig('template/images/testing.png')
picture = "testing.png"
return render_to_response('Test.html', {'picture': picture}, RequestContext(request))
希望有人知道如何解决我的麻烦。
多谢！ 蒂杰尔
I've set up a Django project in which i create random points. These random points are stored in a database(sqlite) (i can see them via the admin website and change the values, so this works).
If i the write a script i can access the points and print them in a plot. See code below.
But if I then want to mine these points to sort them or only plot a selection of the dataset i seem to have trouble. If i readout the values they are not connected anymore and sorting x would mix up the point set.
Is there a way to sort the data set to a minimum value of in this case X and the sort the values and print the set? (keep all x, y, z and name value of the point intact?) (see answer below, point in Point3D.objects.all().order_by('x'):)
If i now want to to have the values of x between x = 12 and x = 30? how can i add this extra filter?
My code is as follows:
models.py:
class Point3D(models.Model):
name = models.CharField(max_length = 10)
x = models.DecimalField(max_digits=5, decimal_places=2)
y = models.DecimalField(max_digits=5, decimal_places=2)
z = models.DecimalField(max_digits=5, decimal_places=2)
generate the points:
from books.models import Point3D
def points():
for i in range(20):
x = random.randint(0,100)
y = random.randint(0,100)
z = random.randint(0,100)
p = Point3D(name = x , x = x ,y = y,z = z)
# print 'test'
p.save()
#
points()
in views.py:
def ThreeGraphs(request):
fig = Figure()
fig.suptitle('2D-punten')
ax = fig.add_subplot(111)
for point in Point3D.objects.all():
print point
name = int(point.name)
xs = int(point.x)
ys = int(point.y)
zs = int(point.z)
print (xs, ys, zs)
ax.plot(xs, ys, 'bo' )
HttpResponse(mimetype="image/png")
FigureCanvas(fig)
fig.savefig('template/images/testing.png')
picture = "testing.png"
return render_to_response('Test.html', {'picture': picture}, RequestContext(request))
Hope anyone knows how to solve my trouble.
Thanks a lot!
Tijl
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您需要这样做：
这将按“x”字段排序返回点。您可以使用 order_by('-x') 来反转排序顺序。
You need to to this:
This will return the points in sorted order by the 'x' field. You can say order_by('-x') to reverse the sort order.