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Case objects vs Enumerations in Scala
...g difference is that Enumerations come with support for instantiating them from some name String. For example:
object Currency extends Enumeration {
val GBP = Value("GBP")
val EUR = Value("EUR") //etc.
}
Then you can do:
val ccy = Currency.withName("EUR")
This is useful when wishing to pers...
capturing self strongly in this block is likely to lead to a retain cycle
...y access of self.timerDisp - you can't refer to self or properties on self from within a block that will be strongly retained by self.
You can get around this by creating a weak reference to self before accessing timerDisp inside your block:
__weak typeof(self) weakSelf = self;
[player addPeriodic...
Remove leading comma from a string
...lit("','");
["first string", "more", "even more"]
To extract a substring from a string I usually use slice() but substr() and substring() also do the job.
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Removing item from vector, while in C++11 range 'for' loop?
...rate over every item, do calculations with it, and then possibly remove it from the container. Erase-remove says that you just erase elements for which a predicate returns true, AFAIU, and it seems better this way to not mix iteration logic in with the predicate.
– Seth Carnegi...
Use JNI instead of JNA to call native code?
...od which uses this byte buffer. This would require you to copy this buffer from c to java, then copy it back from java to c. In this case jni will win in performance because you can keep and modify this buffer in c, without copying.
These are the problems I've encountered. Maybe there's more. But ...
Python: How would you save a simple settings/config file?
... reasons to use a different format.
Write a file like so:
# python 2.x
# from ConfigParser import SafeConfigParser
# config = SafeConfigParser()
# python 3.x
from configparser import ConfigParser
config = ConfigParser()
config.read('config.ini')
config.add_section('main')
config.set('main', 'key...
Exif manipulation library for python [closed]
...u might want to check out exif-py:
Python library to extract EXIF data from tiff and jpeg files. Very easy to use - $ ./EXIF.py image.jpg
or the Python Imaging Library (PIL):
The Python Imaging Library (PIL) adds image processing capabilities to your Python interpreter. This library suppor...
How should I unit test threaded code?
...I'm working on a project that is inherently multithreaded. Events come in from the operating system and I have to process them concurrently.
The simplest way to deal with testing complex, multithreaded application code is this: If its too complex to test, you're doing it wrong. If you have a s...
Position of least significant bit that is set
.../optimisation discussion attached. My favourite solution for your problem (from that site) is «multiply and lookup»:
unsigned int v; // find the number of trailing zeros in 32-bit v
int r; // result goes here
static const int MultiplyDeBruijnBitPosition[32] =
{
0, 1, 28, 2, 29, 14,...
Sort array of objects by object fields
...
Use usort, here's an example adapted from the manual:
function cmp($a, $b) {
return strcmp($a->name, $b->name);
}
usort($your_data, "cmp");
You can also use any callable as the second argument. Here are some examples:
Using anonymous functions (from...