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Understanding dispatch_async
...to run tasks in the background.
For instance, if I am downloading a file from the internet and I want to update the user on the progress of the download, I will run the download in the priority default queue and update the UI in the main queue asynchronously.
dispatch_async(dispatch_get_global_qu...
JavaScript private methods
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If you make an object McDonalds() inherit from Restaurant() McDonalds can't override private methods if you declare them in this way. Well, actually you can, but it will not work if some other method calls the private, it will call the original version of the method ...
Does use of final keyword in Java improve the performance?
...le objects, on the other hand, can have arbitrarily complex state spaces.. From my personal experience, using the keyword final should highlight the intent of the developer to lean toward immutability, not to "optimize" code. I encourage you to read this chapter, fascinating !
–...
Reading a simple text file
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This is how I do it:
public static String readFromAssets(Context context, String filename) throws IOException {
BufferedReader reader = new BufferedReader(new InputStreamReader(context.getAssets().open(filename)));
// do reading, usually loop until end of file r...
Floating point vs integer calculations on modern hardware
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Alas, I can only give you an "it depends" answer...
From my experience, there are many, many variables to performance...especially between integer & floating point math. It varies strongly from processor to processor (even within the same family such as x86) because diffe...
PHP Timestamp into DateTime
...ime, but the DateTime constructor does support creating instances directly from timestamps. According to this documentation, all you need to do is prepend the timestamp with an @ character:
$timestamp = strtotime('Mon, 12 Dec 2011 21:17:52 +0000');
$dt = new DateTime('@' . $timestamp);
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Run a single Maven plugin execution?
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As noted in How to execute maven plugin execution directly from command line?, this
functionality has been implemented as MNG-5768, and is available in Maven 3.3.1.
The change will:
extend direct plugin invocation syntax to allow optional @execution-id parameter, e.g., org.apach...
Unicode (UTF-8) reading and writing to files in Python
...an io.open function, which has an encoding parameter.
Use the open method from the io module.
>>>import io
>>>f = io.open("test", mode="r", encoding="utf-8")
Then after calling f's read() function, an encoded Unicode object is returned.
>>>f.read()
u'Capit\xe1l\n\n'
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Create a pointer to two-dimensional array
...is provided by the array l_matix itself. The pointers to them take storage from where-ever they are declared in and as (stack, static data segment, ...).
– Johannes Schaub - litb
Jun 27 '09 at 19:32
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Use different Python version with virtualenv
...on-config will be invoked with confusing consequences. See this bug report from 2011 github.com/pypa/virtualenv/issues/169 and my question stackoverflow.com/questions/42020937/…
– Laryx Decidua
Feb 23 '18 at 11:16
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