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How to len(generator()) [duplicate]
...e no length, they aren't collections after all.
Generators are functions with a internal state (and fancy syntax). You can repeatedly call them to get a sequence of values, so you can use them in loop. But they don't contain any elements, so asking for the length of a generator is like asking for t...
What's the difference between a Python “property” and “attribute”?
...hon encounters the following code:
spam = SomeObject()
print(spam.eggs)
it looks up eggs in spam, and then examines eggs to see if it has a __get__, __set__, or __delete__ method — if it does, it's a property. If it is a property, instead of just returning the eggs object (as it would for ...
snprintf and Visual Studio 2010
...ented snprintf in Visual Studio 2015. On earlier versions you can simulate it as below.
Long version:
Here is the expected behavior for snprintf:
int snprintf( char* buffer, std::size_t buf_size, const char* format, ... );
Writes at most buf_size - 1 characters to a buffer. The resulting
...
What are good uses for Python3's “Function Annotations”
...semantics like state restrictions, threads that are allowed to access, architecture limitations, etc., and there are quite a few tools that can then read these and process them to provide assurances beyond what you get from the compilers. You could even write things that check preconditions/postcond...
In which situations do we need to write the __autoreleasing ownership qualifier under ARC?
...toreleased on return.
All of this is very well explained in the ARC transition guide.
In your NSError example, the declaration means __strong, implicitly:
NSError * e = nil;
Will be transformed to:
NSError * __strong error = nil;
When you call your save method:
- ( BOOL )save: ( NSError * ...
How to pretty-print a numpy.array without scientific notation and with given precision?
...ould use the numpy.printoptions context manager.
For example, inside the with-suite precision=3 and suppress=True are set:
x = np.random.random(10)
with np.printoptions(precision=3, suppress=True):
print(x)
# [ 0.073 0.461 0.689 0.754 0.624 0.901 0.049 0.582 0.557 0.348]
But out...
Shared-memory objects in multiprocessing
... have a function func that takes in this giant array as input (together with some other parameters). func with different parameters can be run in parallel. For example:
...
Outputting data from unit test in python
If I'm writing unit tests in python (using the unittest module), is it possible to output data from a failed test, so I can examine it to help deduce what caused the error? I am aware of the ability to create a customized message, which can carry some information, but sometimes you might deal with m...
How to get URL of current page in PHP [duplicate]
... what info is available in the $_SERVER array, see the PHP manual page for it.
If you also need the query string (the bit after the ? in a URL), that part is in this variable:
$_SERVER['QUERY_STRING']
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What does “#define _GNU_SOURCE” imply?
...
Defining _GNU_SOURCE has nothing to do with license and everything to do with writing (non-)portable code. If you define _GNU_SOURCE, you will get:
access to lots of nonstandard GNU/Linux extension functions
access to traditional functions which were omitted from...