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Is it better in C++ to pass by value or pass by constant reference?
...r iterators and for function objects (lambdas, classes deriving from std::*_function).
This was especially true before the existence of move semantics. The reason is simple: if you passed by value, a copy of the object had to be made and, except for very small objects, this is always more expensive...
Get names of all keys in the collection
...You could do this with MapReduce:
mr = db.runCommand({
"mapreduce" : "my_collection",
"map" : function() {
for (var key in this) { emit(key, null); }
},
"reduce" : function(key, stuff) { return null; },
"out": "my_collection" + "_keys"
})
Then run distinct on the resulting collecti...
How do I copy to the clipboard in JavaScript?
... API documentation on Overriding the copy event.
Allows you to modify what appears on the clipboard from any copy event, can include other formats of data other than plain text.
Not covered here as it doesn't directly answer the question.
General development notes
Don't expect clipboard related ...
Flatten an Array of Arrays in Swift
...rrays: FlattenBidirectionalCollection<Array<Array<Int>>>(_base: [[1, 2, 3], [4], [5, 6, 7, 8, 9]])). Your point is valid though that you can access it like a flat array, so it would seem that that the CustomStringConvertable implementation is misleading. Your code snippet was and...
Height equal to dynamic width (CSS fluid layout) [duplicate]
... percentage which will be calculated depending on the current width:
.some_element {
position: relative;
width: 20%;
height: 0;
padding-bottom: 20%;
}
This works well in all major browsers.
JSFiddle: https://jsfiddle.net/ayb9nzj3/
...
Getting the SQL from a Django QuerySet [duplicate]
...et = MyModel.objects.all()
>>> print(queryset.query)
SELECT "myapp_mymodel"."id", ... FROM "myapp_mymodel"
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c++ Timer使用总结 - C/C++ - 清泛网 - 专注C/C++及内核技术
...均提供实例参考。窗口应用程序使用Timer：
#define TIMER_ID 1000 //定时器ID，可任意。触发后回调函数中用于区别不同的定时器以执行不同的任务
SetTimer(TIMER_ID, 1000 , NULL); //启动定时器，1秒后触发
KillTimer(TIMER_ID); //取消定时器
...
Is embedding background image data into CSS as Base64 good or bad practice?
...mages as data into CSS or HTML templates could be beneficial on mobile web apps. You should measure usage on a case-by-case basis -- I'm not advocating that data URIs should be used everywhere in a mobile web app.
Note that mobile browsers have limitations on total size of files that can be cached....
How should a model be structured in MVC? [closed]
...a mock database dependency in your model):
class Database {
protected $_conn;
public function __construct($connection) {
$this->_conn = $connection;
}
public function ExecuteObject($sql, $data) {
// stuff
}
}
abstract class Model {
protected $_db;
public fu...
Divide a number by 3 without using *, /, +, -, % operators
...(int argc, char *argv[])
{
int num = 1234567;
int den = 3;
div_t r = div(num,den); // div() is a standard C function.
printf("%d\n", r.quot);
return 0;
}
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