大约有 42,000 项符合查询结果（耗时：0.0341秒） [XML]
Waiting on a list of Future
...n use a CompletionService to receive the futures as soon as they are ready and if one of them throws an exception cancel the processing. Something like this:
Executor executor = Executors.newFixedThreadPool(4);
CompletionService<SomeResult> completionService =
new ExecutorCompletionSe...
Running shell command and capturing the output
I want to write a function that will execute a shell command and return its output as a string , no matter, is it an error or success message. I just want to get the same result that I would have gotten with the command line.
...
Windows batch files: .bat vs .cmd?
As I understand it, .bat is the old 16-bit naming convention, and .cmd is for 32-bit Windows, i.e., starting with NT. But I continue to see .bat files everywhere, and they seem to work exactly the same using either suffix. Assuming that my code will never need to run on anything older than NT, d...
Create a list from two object lists with linq
...st2).ToList();
This will return a List in which the two lists are merged and doubles are removed. If you don't specify a comparer in the Union extension method like in my example, it will use the default Equals and GetHashCode methods in your Person class. If you for example want to compare person...
CPU Privilege Rings: Why rings 1 and 2 aren't used?
...the modern protection model) only has a concept of privileged (ring 0,1,2) and unprivileged, the benefit to rings 1 and 2 were diminished greatly.
The intent by Intel in having rings 1 and 2 is for the OS to put device drivers at that level, so they are privileged, but somewhat separated from the r...
Changing the case of a string in Eclipse
...make a lowercase string uppercase using Eclipse? I want to select a string and either uppercase it or lowercase it. Is there a shortcut for doing this?
...
Activity transition in Android
How can I define the transition between two activities for Android 1.5 and later?
I would like an activity to fade in.
14 ...
How to convert a string to lower case in Bash?
...
The are various ways:
POSIX standard
tr
$ echo "$a" | tr '[:upper:]' '[:lower:]'
hi all
AWK
$ echo "$a" | awk '{print tolower($0)}'
hi all
Non-POSIX
You may run into portability issues with the following examples:
Bash 4.0
$ echo "${a,,}"
hi all...
Python: fastest way to create a list of n lists
...None, n)]
It does not have to create a new int object in every iteration and is about 15 % faster on my machine.
Edit: Using NumPy, you can avoid the Python loop using
d = numpy.empty((n, 0)).tolist()
but this is actually 2.5 times slower than the list comprehension.
...
How to express a NOT IN query with ActiveRecord/Rails?
...e come to this, if you are using Rails 4 look at the answers by Trung Lê` and VinniVidiVicci.
15 Answers
...