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How to pick just one item from a generator?
... next(gen, default) may also be used to avoid the StopIteration exception. For example next(g, None) for a generator of strings will either yield a string or None after the iteration was finished.
– Attila
Mar 6 '13 at 14:18
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What are type lambdas in Scala and what are their benefits?
...g with higher-kinded types.
Consider a simple example of defining a monad for the right projection of Either[A, B]. The monad typeclass looks like this:
trait Monad[M[_]] {
def point[A](a: A): M[A]
def bind[A, B](m: M[A])(f: A => M[B]): M[B]
}
Now, Either is a type constructor of two argu...
Random string generation with upper case letters and digits
...n one line:
''.join(random.choice(string.ascii_uppercase + string.digits) for _ in range(N))
or even shorter starting with Python 3.6 using random.choices():
''.join(random.choices(string.ascii_uppercase + string.digits, k=N))
A cryptographically more secure version; see https://stackoverflow....
Django database query: How to get object by id?
...
If you want to get an object, using get() is more straightforward:
obj = Class.objects.get(pk=this_object_id)
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Git Bash is extremely slow on Windows 7 x64
...tu during the development of a small project, frequently flipping back and forth between the two. The issue is that Git Bash consistently becomes slow.
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Will the Garbage Collector call IDisposable.Dispose for me?
...k
see http://msdn.microsoft.com/en-us/library/system.object.finalize.aspx for more information
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rgdal package installation
...package page on CRAN, you will see the following :
SystemRequirements: for building from source: GDAL >= 1.7.1 library
from http://trac.osgeo.org/gdal/wiki/DownloadSource and PROJ.4 (proj >= 4.4.9) from http://trac.osgeo.org/proj/; GDAL OSX frameworks built by William Kyngesburye at http...
What does the Ellipsis object do?
...wer from there:
Ellipsis is an object that can appear in slice notation. For example:
myList[1:2, ..., 0]
Its interpretation is purely up to whatever implements the __getitem__ function and sees Ellipsis objects there, but its main (and intended) use is in the numpy third-party library, which a...
Efficient Algorithm for Bit Reversal (from MSB->LSB to LSB->MSB) in C
...e256[p[3]];
You can extend this idea to 64-bit ints, or trade off memory for speed (assuming your L1 Data Cache is large enough), and reverse 16 bits at a time with a 64K-entry lookup table.
Others
Simple
unsigned int v; // input bits to be reversed
unsigned int r = v & 1; // r will b...
Android - Camera preview is sideways
... how I implement it:
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
if (isPreviewRunning) {
mCamera.stopPreview();
}
Parameters parameters = mCamera.getParameters();
Display display = ((WindowManager)getSystemService(WINDOW...