大约有 30,000 项符合查询结果（耗时：0.0344秒） [XML]
How do I get a class instance of generic type T?
...
The short answer is, that there is no way to find out the runtime type of generic type parameters in Java. I suggest reading the chapter about type erasure in the Java Tutorial for more details.
A popular solution to this is to pass the Class of the type parameter into the constructor...
How to detect if a script is being sourced
...estfile.ksh:
cat >testfile.ksh
chmod +x testfile.ksh
Than run it two time:
./testfile.ksh
. ./testfile.ksh
ls -l /tmp/ksh-*.log
-rw-r--r-- 1 user user 2183 avr 11 13:48 /tmp/ksh-9725.log
-rw-r--r-- 1 user user 2140 avr 11 13:48 /tmp/ksh-9781.log
echo $$
9725
and see:
diff /tmp/ksh-{9...
How to set input type date's default value to today?
...
for .net users: DateTime.Today.ToString("yyyy-MM-dd")
– dvdmn
May 14 '14 at 12:19
3
...
Decorators with parameters?
...ep
@types(str, int) # arg1 is str, arg2 is int
def string_multiply(text, times):
return text * times
print(string_multiply('hello', 3)) # Prints hellohellohello
print(string_multiply(3, 3)) # Fails miserably with TypeError
A final note: here I'm not using functools.wraps for the...
Python mysqldb: Library not loaded: libmysqlclient.18.dylib
...s in your source files.
Also compared to yoshisurfs answer, most of the time when mysql gets installed the mysql directory should be renamed to just mysql, not the whole file name, for ease of use.
export DYLD_LIBRARY_PATH=/usr/local/mysql/lib:$DYLD_LIBRARY_PATH
...
Principal component analysis in Python
...g signal is a sinusoidally modulated image
img = lena()
t = np.arange(100)
time = np.sin(0.1*t)
real = time[:,np.newaxis,np.newaxis] * img[np.newaxis,...]
# we add some noise
noisy = real + np.random.randn(*real.shape)*255
# (observations, features) matrix
M = noisy.reshape(noisy.shape[0],-1)
# s...
Best practices for circular shift (rotate) operations in C++
... MIPS that only provide a rotate-right. (This optimizes away with compile-time-constant counts.)
Fun fact: ARM doesn't really have dedicated shift/rotate instructions, it's just MOV with the source operand going through the barrel-shifter in ROR mode: mov r0, r0, ror r1. So a rotate can fold into...
Greenlet Vs. Threads
...es to complete the work and this test shows nothing (also did you take the timeout off of the gevent.joinall() call?). Try using a thread pool of about 50 threads, see my answer: stackoverflow.com/a/51932442/34549
– zzzeek
Aug 20 '18 at 14:14
...
How to write a scalable Tcp/Ip based server
... about changing. For one, only have a single BeginAccept called at any one time. There used to be a very annoying .net bug around this, which was years ago so I don't recall the details.
Also, in the ReceiveCallback code, we process anything received from the socket before we queue the next receiv...
multiprocessing: sharing a large read-only object between processes?
...objects could be pickled Python objects to save a tiny bit of file reading time.
Write a startup program that (1) reads your original gigantic object and writes a page-structured, byte-coded file using seek operations to assure that individual sections are easy to find with simple seeks. This is wh...