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Create singleton using GCD's dispatch_once in Objective-C
...er here: instancetype
+ (instancetype)sharedInstance
{
static dispatch_once_t once;
static id sharedInstance;
dispatch_once(&once, ^
{
sharedInstance = [self new];
});
return sharedInstance;
}
+ (Class*)sharedInstance
{
static dispatch_once_t once;
...
How to install Xcode Command Line Tools
How do I get the command-line build tools installed with the current Xcode/Mac OS X v10.8 (Mountain Lion) or later?
13 Answ...
How to get overall CPU usage (e.g. 57%) on Linux [closed]
...s was not tested nor used, it's an idea for people who do not want to install a utility or for something that works in any distribution. Some people think you can "apt-get install" anything.
NOTE: this is not the current CPU usage, but the overall CPU usage in all the cores since the system bootup...
How do I fix PyDev “Undefined variable from import” errors?
...ncing the same issue with latest Eclipse and PyDev. I can navigate between all modules, so why code-analysis can't do the same?
– Adam
Sep 3 '14 at 11:41
3
...
What's the shortest code to cause a stack overflow? [closed]
...
All these answers and no Befunge? I'd wager a fair amount it's shortest solution of them all:
1
Not kidding. Try it yourself: http://www.quirkster.com/iano/js/befunge.html
EDIT: I guess I need to explain this one. The 1 o...
jQuery get values of checked checkboxes into array
I am trying to get values of all checkboxes that are currently checked and store them into an array. Here is my code so far:
...
Get difference between two lists
...hat this only returns the temp1-temp2? .. As other said in order to return all the differences you have to use the sysmetric difference: list(set(temp1) ^ set(temp2))
– rkachach
Feb 16 '16 at 16:00
...
SVN Error - Not a working copy
...min to filter out old projects I no longer need. So my repository contains all the info I need, but has a new UUID. In this case, I'm just going to tar up the changed files, get a fresh checkout, and then untar.
– Drarok
Aug 28 '09 at 15:21
...
How do I pass a method as a parameter in Python
...thodToRun()
return result
obj.method2(obj.method1)
Note: I believe a __call__() method does exist, i.e. you could technically do methodToRun.__call__(), but you probably should never do so explicitly. __call__() is meant to be implemented, not to be invoked from your own code.
If you wanted me...
Cartesian product of multiple arrays in JavaScript
...S
Original 2017 Answer: 2-line answer with vanilla JS:
(see updates below)
All of the answers here are overly complicated, most of them take 20 lines of code or even more.
This example uses just two lines of vanilla JavaScript, no lodash, underscore or other libraries:
let f = (a, b) => [].concat...