大约有 47,000 项符合查询结果（耗时：0.0566秒） [XML]
Is it safe to ignore the possibility of SHA collisions in practice?
... on Earth within the next second, obliterating civilization-as-we-know-it, and killing off a few billion people? It can be argued that any unlucky event with a probability lower than that is not actually very important.
If we have a "perfect" hash function with output size n, and we have p messages...
In which situations do we need to write the __autoreleasing ownership qualifier under ARC?
...
__autoreleasing to denote arguments that are passed by reference (id *) and are autoreleased on return.
All of this is very well explained in the ARC transition guide.
In your NSError example, the declaration means __strong, implicitly:
NSError * e = nil;
Will be transformed to:
NSError * ...
For-each over an array in JavaScript
...-of loop (ES2015+ only),
Array#forEach (spec | MDN) (or its relatives some and such) (ES5+ only),
a simple old-fashioned for loop,
or for-in with safeguards.
But there's lots more to explore, read on...
JavaScript has powerful semantics for looping through arrays and array-like objects. I've s...
How to apply a Git patch to a file with a different name and path?
...ories. In one, I make changes to file ./hello.test . I commit the changes and create a patch from that commit with git format-patch -1 HEAD . Now, I have a second repository that contains a file that has the same contents as hello.test but is placed in a different directory under a different name:...
Case insensitive access for generic dictionary
...t where you try to get a value. If you think about it, "foo".GetHashCode() and "FOO".GetHashCode() are totally different so there's no reasonable way you could implement a case-insensitive get on a case-sensitive hash map.
You can, however, create a case-insensitive dictionary in the first place us...
How can I tell if a DOM element is visible in the current viewport?
...
Update: Time marches on and so have our browsers. This technique is no longer recommended and you should use Dan's solution if you do not need to support version of Internet Explorer before 7.
Original solution (now outdated):
This will check if ...
Python's os.makedirs doesn't understand “~” in my path
...
You need to expand the tilde manually:
my_dir = os.path.expanduser('~/some_dir')
share
|
improve this answer
|
f...
MAC addresses in JavaScript
...
Using Java (with a signed applet)
Using signed Javascript, which in FF (and Mozilla in general) gets higher privileges than normal JS (but it is fairly complicated to set up)
share
|
improve thi...
Git, How to reset origin/master to a commit?
I reset my local master to a commit by this command:
4 Answers
4
...
What happens to a declared, uninitialized variable in C? Does it have a value?
...
Static variables (file scope and function static) are initialized to zero:
int x; // zero
int y = 0; // also zero
void foo() {
static int x; // also zero
}
Non-static variables (local variables) are indeterminate. Reading them prior to assigning a ...