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Check if OneToOneField is None in Django
...ately, this doesn't work all the time. In case you want to work with select_related() now or in the future -- or maybe even to be sure you also handle other sorts of magic which may happen elsewhere -- you have to extend the test as follows: if hasattr(object, 'onetoonerevrelattr') and object.onetoo...
What's the _ underscore representative of in Swift References?
...
Both answers were correct but I want to clarify a little bit more.
_ is used to modify external parameter name behavior for methods.
In Local and External Parameter Names for Methods section of the documentation, it says:
Swift gives the first parameter name in a method a local paramete...
PHP passing $_GET in linux command prompt
...ipt.php -f=world
$opts = getopt('f:');
echo $opts['f']; // prints world
$_GET refers to the HTTP GET method parameters, which are unavailable in command line, since they require a web server to populate.
If you really want to populate $_GET anyway, you can do this:
// bash command:
// export Q...
How do I show the value of a #define at compile-time?
... This also works great with Xcode 8, e.g. replacing ABC with __IPHONE_9_3.
– funroll
Oct 11 '16 at 19:50
...
What is the difference between “px”, “dip”, “dp” and “sp”?
...
@android_developer (5 comments above) dp does not have the exact same physical length. (Although it is close.) See @Fraggle's comment about bucketing. What this means is that 48dp will be roughly 8mm (0.3 inch), but it may vary up to...
What is the best way to ensure only one instance of a Bash script is running? [duplicate]
...e
### HEADER ###
LOCKFILE="/var/lock/`basename $0`"
LOCKFD=99
# PRIVATE
_lock() { flock -$1 $LOCKFD; }
_no_more_locking() { _lock u; _lock xn && rm -f $LOCKFILE; }
_prepare_locking() { eval "exec $LOCKFD>\"$LOCKFILE\""; trap _no_more_locking EXIT; }
# ON START
_prepare_l...
整合phpcms v9和discuz X3.2实现同步登陆、退出免激活 - 更多技术 - 清泛网...
...、退出免激活
首先，初学者请先查看视频教程《phpcms_v9与ucenter整合屏幕录制资料》，介绍了详细的操作步骤，简单易懂。
原理：phpcms中的phpsso类似于康盛的ucenter软件，也是一个整合多系统同步通信的解决方案，不过这里...
How do I use prepared statements in SQlite in Android?
... Below are some examples:
Create a table
String sql = "CREATE TABLE table_name (column_1 INTEGER PRIMARY KEY, column_2 TEXT)";
SQLiteStatement stmt = db.compileStatement(sql);
stmt.execute();
The execute() method does not return a value so it is appropriate to use with CREATE and DROP but not in...
Python Pandas: Get index of rows which column matches certain value
...tion and then create slices for use in iloc(). The only thing I see is get_loc, but it cannot take an array.
– sheridp
Apr 21 '16 at 0:47
3
...
Objective-C declared @property attributes (nonatomic, copy, strong, weak)
...maticReferenceCounting.html#ownership.spelling.property
assign implies __unsafe_unretained ownership.
copy implies __strong ownership, as well as the usual behavior of copy
semantics on the setter.
retain implies __strong ownership.
strong implies __strong ownership.
unsafe...