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Understanding __get__ and __set__ and Python descriptors
... that great).
A descriptor is defined on a class, but is typically called from an instance. When it's called from an instance both instance and owner are set (and you can work out owner from instance so it seems kinda pointless). But when called from a class, only owner is set – which is why it's...
How to find serial number of Android device?
...VICE);
String uid = tManager.getDeviceId();
getSystemService is a method from the Activity class. getDeviceID() will return the MDN or MEID of the device depending on which radio the phone uses (GSM or CDMA).
Each device MUST return a unique value here (assuming it's a phone). This should wor...
Are tuples more efficient than lists in Python?
...
Although the suggestion you can conclude anything from counting ops is misguided, this does show the key difference: constant tuples are stored as such in the bytecode and just referenced when used, whereas lists need to be built at runtime.
– poolie
...
What does the restrict keyword mean in C++?
...l only
be accessed through that pointer (and pointers copied
from it).
In C++ compilers that support it it should probably behave the same as in C.
See this SO post for details: Realistic usage of the C99 ‘restrict’ keyword?
Take half an hour to skim through Ericson's paper, i...
Why does i = i + i give me 0?
... 0 on the first few iterations, but speed of output is obscuring that fact from the OP). Why is it accepted?
– Lightness Races in Orbit
Jun 12 '14 at 10:09
...
PHP passing $_GET in linux command prompt
...> value
)
*/
You can also execute a given script, populate $_GET from the command line, without having to modify said script:
export QUERY_STRING="var=value&arg=value" ; \
php -e -r 'parse_str($_SERVER["QUERY_STRING"], $_GET); include "index.php";'
Note that you can do the same with...
How to run Rake tasks from within Rake tasks?
...you'd rather stick to rake's idioms, here are your possibilities, compiled from past answers:
This always executes the task, but it doesn't execute its dependencies:
Rake::Task["build"].execute
This one executes the dependencies, but it only executes the task if
it has not already been invoked:...
Is it possible to modify variable in python that is in outer, but not global, scope?
...
@kindall that's a great hack - it's minimally different from the Python 3 syntax and much more readable than passing around a mutable object.
– dimo414
Sep 1 '15 at 0:17
...
Why is XOR the default way to combine hashes?
...
answering to the exercise: from the 16 possible different a XXX b operations (0, a & b, a > b, a, a < b, b, a % b, a | b, !a & !b, a == b, !b, a >= b, !a, a <= b, !a | !b, 1), the following have 50%-50% distributions of 0s and 1s, a...
What is a semaphore?
...ey will be sufficient to protect that resource and prevent multiple people from using it simultaneously.
If there are multiple bathrooms, one might be tempted to key them alike and make multiple keys - this is similar to a semaphore being mis-used. Once you have a key you don't actually know which ...