大约有 40,000 项符合查询结果（耗时：0.0596秒） [XML]
How can I remove all objects but one from the workspace in R?
I have a workspace with lots of objects and I would like to remove all but one. Ideally I would like to avoid having to type rm(obj.1, obj.2... obj.n) . Is it possible to indicate remove all objects but these ones ?
...
How to check if a value exists in a dictionary (python)
...
it wasn't necesarry after all, unless run on bigger dict. I guess overhead in values() is caused by copying the value list and in viewvalues() by maintaining the view alive.
– soulcheck
Nov 21 '11 at 17:12
...
Print in one line dynamically
...
From http://docs.python.org/reference/simple_stmts.html#print: > A '\n' character is written at the end, unless the print statement ends with a comma. This is the only action if the statement contains just the keyword print.
– ewall
...
How do I run all Python unit tests in a directory?
...it test module is of the form test_*.py . I am attempting to make a file called all_test.py that will, you guessed it, run all files in the aforementioned test form and return the result. I have tried two methods so far; both have failed. I will show the two methods, and I hope someone out there ...
How to combine two or more querysets in a Django view?
...sets into a list is the simplest approach. If the database will be hit for all querysets anyway (e.g. because the result needs to be sorted), this won't add further cost.
from itertools import chain
result_list = list(chain(page_list, article_list, post_list))
Using itertools.chain is faster than...
Flatten an Array of Arrays in Swift
...
Just to state this more generally, flatMap is available as of Swift 1.2.
– Mick MacCallum
Apr 24 '15 at 4:56
3
...
What is “rvalue reference for *this”?
Came across a proposal called "rvalue reference for *this" in clang's C++11 status page .
3 Answers
...
How to return an array from JNI to Java?
...th the JNI function NewObjectArray(). From the perspective of JNI, that's all a two dimensional array is, an object array containing a number of other inner arrays.
The following for loop creates the inner arrays which are of type int[] using the JNI function NewIntArray(). If you just wanted t...
How can I determine whether a 2D Point is within a Polygon?
...integers. Many systems use integers for UI painting (pixels are ints after all), but macOS for example uses float for everything. macOS only knows points and a point can translate to one pixel, but depending on monitor resolution, it might translate to something else. On retina screens half a point ...
How to enumerate an enum with String type?
...h Xcode 10), just add protocol conformance to CaseIterable to benefit from allCases. To add this protocol conformance, you simply need to write somewhere:
extension Suit: CaseIterable {}
If the enum is your own, you may specify the conformance directly in the declaration:
enum Suit: String, CaseIte...