大约有 47,000 项符合查询结果（耗时：0.0600秒） [XML]
How do I get the object if it exists, or None if it does not exist?
...u can do it this way:
go = Content.objects.filter(name="baby").first()
Now go variable could be either the object you want or None
Ref: https://docs.djangoproject.com/en/1.8/ref/models/querysets/#django.db.models.query.QuerySet.first
...
What is “2's Complement”?
...ition and subtraction remains difficult.
So along comes two's complement. Now you can store positive and negative integers and perform arithmetic with relative ease. There are a number of methods to convert a number into two's complement. Here's one.
Convert Decimal to Two's Complement
Convert t...
IOException: read failed, socket might closed - Bluetooth on Android 4.3
...b/android-4.3_r2/core/java/android/bluetooth/BluetoothDevice.java#L1037).
Now, when I receive that exception, I instantiate a fallback BluetoothSocket, similar to the source code below. As you can see, invoking the hidden method createRfcommSocket via reflections. I have no clue why this method is ...
What is “the inverse side of the association” in a bidirectional JPA OneToMany/ManyToOne association
...nship will not be bidirectional (the inverse aka "many" side will have no knowledge of its "owner"). This can be desirable for encapsulation/loose coupling:
// "One" Customer owns the associated orders by storing them in a customer_orders join table
public class Customer {
@OneToMany(cascade = ...
WatiN or Selenium? [closed]
...ution.
Script creation tools are independent projects; there are 2 that I know of: Wax (Excel based, hosted on CodePlex) and WatiN Test Record (hosted on SourceForge). Neither is as robust as Selenium IDE.
Very good IE support. Can attach and detach to/from running instances. Can access native wind...
Why do == comparisons with Integer.valueOf(String) give different results for 127 and 128?
...ird value returns true - 128 == 128 is evaluated, and is of course, true.
Now, a fair bit happens to make that third result true:
An unboxing conversion occurs with respect to the equivalence operator you're using and the datatypes you have - namely, int and Integer. You're getting an Integer fr...
HTML: Include, or exclude, optional closing tags?
...
i see it now. <LI> is like a bullet. Nobody would want to have to wrap an entire bulleted point in <LI>...</LI>. So in that way the LI matches what people would naturally write during markup. Sames goes for a paragr...
What characters are allowed in an email address?
...
Watch out! There is a bunch of knowledge rot in this thread (stuff that used to be true and now isn't).
To avoid false-positive rejections of actual email addresses in the current and future world, and from anywhere in the world, you need to know at least...
Run cURL commands from Windows console
...ble, but rather just need to e.g. see or save the results of a GET request now and again, can use powershell directly. From a normal command prompt, type:
powershell -Command "(new-object net.webclient).DownloadString('http://example.com')"
which, while a bit wordy, is similar to typing
curl htt...
How to set a Default Route (To an Area) in MVC
... {
return (ch == '/');
}
return true;
}
}
Now as stated, this isn't a concrete engine, so you have to create that as well. This part, fortunately, is much easier, all we need to do is set the default formats and actually create the views:
AreaAwareViewEngine.cs
publ...