大约有 46,000 项符合查询结果（耗时：0.0280秒） [XML]
Overloading Macro on Number of Arguments
...OO(foo,bar,baz) # expands to FOO3(foo,bar,baz)
If you want a fourth one:
#define GET_MACRO(_1,_2,_3,_4,NAME,...) NAME
#define FOO(...) GET_MACRO(__VA_ARGS__, FOO4, FOO3, FOO2)(__VA_ARGS__)
FOO(a,b,c,d) # expeands to FOO4(a,b,c,d)
Naturally, if you define FOO2, FOO3 and FOO4, the ...
How to list all the available keyspaces in Cassandra?
I am newbie in Cassandra and trying to implement one toy application using Cassandra. I had created one keyspace and few column families in my Cassandra DB but I forgot the name of my cluster.
...
Create unique constraint with null columns
... (user_id, recipe_id)
WHERE menu_id IS NULL;
This way, there can only be one combination of (user_id, recipe_id) where menu_id IS NULL, effectively implementing the desired constraint.
Possible drawbacks: you cannot have a foreign key referencing (user_id, menu_id, recipe_id), you cannot base CLU...
What does the caret operator (^) in Python do?
...
It's a bitwise XOR (exclusive OR).
It results to true if one (and only one) of the operands (evaluates to) true.
To demonstrate:
>>> 0^0
0
>>> 1^1
0
>>> 1^0
1
>>> 0^1
1
To explain one of your own examples:
>>> 8^3
11
Think about i...
What's the algorithm to calculate aspect ratio?
...",gcd(1024,768));
}
And here's some complete HTML/Javascript which shows one way to detect the screen size and calculate the aspect ratio from that. This works in FF3, I'm unsure what support other browsers have for screen.width and screen.height.
<html><body>
<script type="tex...
Best Practices: Salting & peppering passwords?
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Ok. Seeing as I need to write about this over and over, I'll do one last canonical answer on pepper alone.
The Apparent Upside Of Peppers
It seems quite obvious that peppers should make hash functions more secure. I mean, if the attacker only gets your database, then your users password...
How to make an enum conform to a protocol in Swift?
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Excellent pointer. Was a bit stuck on this one. One question though: Any reason you added the return value of Void to the adjust function?
– jpittman
Jun 7 '14 at 19:45
...
+ operator for array in PHP?
...ts from the right-hand array will be ignored.
So if you do
$array1 = ['one', 'two', 'foo' => 'bar'];
$array2 = ['three', 'four', 'five', 'foo' => 'baz'];
print_r($array1 + $array2);
You will get
Array
(
[0] => one // preserved from $array1 (left-hand array)
[1]...
jQuery: more than one handler for same event
...Both handlers will run, the jQuery event model allows multiple handlers on one element, therefore a later handler does not override an older handler.
The handlers will execute in the order in which they were bound.
share
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`static` keyword inside function?
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Seems like nobody mentioned so far, that static variables inside different instances of the same class remain their state. So be careful when writing OOP code.
Consider this:
class Foo
{
public function call()
{
static $test = 0;
...