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Why does Apple recommend to use dispatch_once for implementing the singleton pattern under ARC?
... it's faster. It's also semantically cleaner, because it also protects you from multiple threads doing alloc init of your sharedInstance--if they all try at the same exact time. It won't allow two instances to be created. The entire idea of dispatch_once() is "perform something once and only once", ...
Regex expressions in Java, \\s vs. \\s+
... regular expression quantifiers, and they perform matches like this (taken from the documentation):
Greedy quantifiers
X? X, once or not at all
X* X, zero or more times
X+ X, one or more times
X{n} X, exactly n times
X{n,} X, at least n times
X{n,m} X, at least n but not more than m times
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How to delete files/subfolders in a specific directory at the command prompt in Windows
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Use single percentage sign if you wish to run direct from command line e.g. %p
– Alex
Mar 9 '14 at 8:24
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How does having a dynamic variable affect performance?
...l to Foo, one for the dynamic addition, and one for the dynamic conversion from dynamic to int. Each one has its own runtime analysis and its own cache of analysis results.
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Struct like objects in Java
...an cluttering it with needless getters and setters.
Java Code Conventions from 1999 and still unchanged.
10.1 Providing Access to Instance and Class Variables
Don't make any instance or class variable public without good reason. Often, instance variables don't need to be explicitly set or got...
What does the 'Z' mean in Unix timestamp '120314170138Z'?
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Yes. 'Z' stands for Zulu time, which is also GMT and UTC.
From http://en.wikipedia.org/wiki/Coordinated_Universal_Time:
The UTC time zone is sometimes denoted by the letter Z—a reference to
the equivalent nautical time zone (GMT), which has been denoted by a Z
since about ...
Read and parse a Json File in C#
...you have a StreamReader anyway, it would be better to deserialize directly from the stream using JsonTextReader as shown in Can Json.NET serialize / deserialize to / from a stream?. The r.ReadToEnd() is not needed.
– dbc
Jun 11 '19 at 19:05
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How to check if a String contains only ASCII?
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From Guava 19.0 onward, you may use:
boolean isAscii = CharMatcher.ascii().matchesAllOf(someString);
This uses the matchesAllOf(someString) method which relies on the factory method ascii() rather than the now deprecated A...
REST API Authentication
... I want to build an API for the application to facilitate interaction with from any platform (Web App, Mobile App). What I'm not understanding is that when using the REST API, how do we authenticate the user.
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What is an abstract class in PHP?
...bstract".
The purpose of this is to provide a kind of template to inherit from and to force the inheriting class to implement the abstract methods.
An abstract class thus is something between a regular class and a pure interface. Also interfaces are a special case of abstract classes where ALL met...