大约有 40,000 项符合查询结果（耗时：0.0571秒） [XML]
Is the != check thread safe?
...blic boolean test() {
return a != a;
}
may produce true. This is the bytecode for test()
ALOAD 0
GETFIELD test/Test1.a : Ljava/lang/Object;
ALOAD 0
GETFIELD test/Test1.a : Ljava/lang/Object;
IF_ACMPEQ L1
...
as we can see it loads field a to local vars twice, it's a non...
Finding ALL duplicate rows, including “elements with smaller subscripts”
...ovide a reproducible example, so here's an illustration kindly contributed by @jbaums
vec <- c("a", "b", "c","c","c")
vec[duplicated(vec) | duplicated(vec, fromLast=TRUE)]
## [1] "c" "c" "c"
Edit: And an example for the case of a data frame:
df <- data.frame(rbind(c("a","a"),c("b","b"),...
Why does sudo change the PATH?
...
it's annoying. period. if it could 'get you trojaned' by sudo it could get you trojaned the same without it. granted, harder, but if you are running code from the wrong place even with your regular user, then things are already bad enough.
– gcb
...
Selenium wait until document is ready
...ed solution only waits for DOM readyState to signal complete. But Selenium by default tries to wait for those (and a little bit more) on page loads via the driver.get() and element.click() methods. They are already blocking, they wait for the page to fully load and those should be working ok.
Probl...
Django database query: How to get object by id?
...turns the identity of an object. In a majority of cases referencing things by id will do the right thing e.g. Class.objects.get(id=this_object_id) work. But that's something to consider I guess.
– Tom
Jul 28 '16 at 20:45
...
How to specify a editor to open crontab file? “export EDITOR=vi” does not work
...
If the crontab is managed by several persons with one user, I recommend to do this in a subshell, so the default editor stays in place.
– Thomas Böhm
Dec 7 '17 at 12:21
...
What does “1 line adds whitespace errors” mean when applying a patch?
...manual explains:
What are considered whitespace errors is controlled
by core.whitespace configuration. By default, trailing whitespaces
(including lines that solely consist of whitespaces) and a space
character that is immediately followed by a tab character inside the
initial indent of ...
EJB's - when to use Remote and/or local interfaces?
...distributing EJBs on a different tier and they fixed the spec (in EJB 2.0) by introducing the concept of Local interfaces so that clients collocated in the same virtual machine with the EJB container can call EJBs using direct method invocation, totally bypassing RMI semantics (and the associated ov...
The Definitive C++ Book Guide and List
..., 2014) (updated for C++11/C++14) An introduction to programming using C++ by the creator of the language. A good read, that assumes no previous programming experience, but is not only for beginners.
Introductory, with previous programming experience
A Tour of C++ (Bjarne Stroustrup) (2nd edition...
Clang vs GCC - which produces faster binaries? [closed]
... rich in polymorphism and templates and but is still
mired in many patches by its not-so-distant past in hacked-together C.
Move semantics are not expressly exploited. It is single-threaded. I
have devoted no serious effort to optimizing it, while the "architecture"
remains so largely ToDo.
I emplo...