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Optimistic vs. Pessimistic locking
...essential that the data is accurately read, with no un-shown changes - the extra locking overhead is worth it.
Oh, and Microsoft SQL server defaults to page locking - basically the row you're reading and a few either side. Row locking is more accurate but much slower. It's often worth setting your...
How to make a class property? [duplicate]
...az.bar == 50
assert foo.bar == 50
The setter didn't work at the time we call Bar.bar, because we are calling
TypeOfBar.bar.__set__, which is not Bar.bar.__set__.
Adding a metaclass definition solves this:
class ClassPropertyMetaClass(type):
def __setattr__(self, key, value):
if key ...
__proto__ VS. prototype in JavaScript
...x = x;
this.y = y;
}
var myPoint = new Point();
// the following are all true
myPoint.__proto__ == Point.prototype
myPoint.__proto__.__proto__ == Object.prototype
myPoint instanceof Point;
myPoint instanceof Object;
Here Point is a constructor function, it builds an object (data structure) p...
Compare object instances for equality by their attributes
...s:
>>> x == y
True
Note that implementing __eq__ will automatically make instances of your class unhashable, which means they can't be stored in sets and dicts. If you're not modelling an immutable type (i.e. if the attributes foo and bar may change value within the lifetime of your obje...
Can a class extend both a class and implement an Interface
...ll also change. Second, inheritance is used to SPECIALIZE, not EXTEND with extra functionality. This is the most misunderstood thing in OOP. As a rule of thumb I tend to extend abstract classes only.
– Michał Rudnicki
Mar 16 '09 at 21:25
...
Best way to do multiple constructors in PHP
...
<?php
class Student
{
public function __construct() {
// allocate your stuff
}
public static function withID( $id ) {
$instance = new self();
$instance->loadByID( $id );
return $instance;
}
public static function withRow( array $row ) {
...
Why can't decimal numbers be represented exactly in binary?
...1/3, 1/9, 1/27, or any rational in decimal notation. We do it by adding an extra symbol. For example, a line over the digits that repeat in the decimal expansion of the number. What we need to represent decimal numbers as a sequence of binary numbers are 1) a sequence of binary numbers, 2) a radix p...
Fastest way to list all primes below N
...4.0 |
| sundaram3 | 416.0 |
+---------------------+-------+
Of all the methods tested, allowing numpy, for n=1000000,
primesfrom2to was the fastest tested.
+---------------------+-------+
| Method | ms |
+---------------------+-------+
| primesfrom2to | 15.9 |
| p...
How to list all installed packages and their versions in Python?
Is there a way in Python to list all installed packages and their versions?
11 Answers
...
Discuz X3涂鸦板无法使用问题解决 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...sh.events.Event;
var result:XML;
var msg:String;
var loader:flash.net.URLLoader;
var request:flash.net.URLRequest;
var variables:flash.net.URLVariables;
var loc1:*;
result = null;...