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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...
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
...
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 * ...
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...
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...
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 ...
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:
...
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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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...
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...