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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.
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Check if a string contains a string in C++
... end = high_resolution_clock::now();
timespan = duration_cast<duration<double>>(end-start);
std::cout << "Processing of " << haystacksCount << " elements took " << timespan.count() << " seconds." << std::endl;
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Copy file or directories recursively in Python
Python seems to have functions for copying files (e.g. shutil.copy ) and functions for copying directories (e.g. shutil.copytree ) but I haven't found any function that handles both. Sure, it's trivial to check whether you want to copy a file or a directory, but it seems like a strange omission.
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How to use a servlet filter in Java to change an incoming servlet request url?
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Implement javax.servlet.Filter.
In doFilter() method, cast the incoming ServletRequest to HttpServletRequest.
Use HttpServletRequest#getRequestURI() to grab the path.
Use straightforward java.lang.String methods like substring(), split(), concat() and so on to extract the part o...
How to pass parameters to ThreadStart method in Thread?
... multiple parameters, and you get compile-time checking without needing to cast from object all the time.
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Checking that a List is not empty in Hamcrest
...(empty())));
empty() is a static in the Matchers class. Note the need to cast the list to Collection, thanks to Hamcrest 1.2's wonky generics.
The following imports can be used with hamcrest 1.3
import static org.hamcrest.Matchers.empty;
import static org.hamcrest.core.Is.is;
import static org.h...
Why does ('0' ? 'a' : 'b') behave different than ('0' == true ? 'a' : 'b') [duplicate]
... not equal to true, though it is not false.
In the first case, when '0' is casted to bool, casting operator returns true for everything that is not 0.
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Is it worth hashing passwords on the client side
...lain text passwords is certainly also able to listen for hashed passwords, and use these captured hashes him/herself to authenticate against your server.
For this matter, more secure authentication protocols usually jump through a number of hoops in order to make sure, that such a replay attack can...
Enums and Constants. Which to use when?
...pe except char like:
enum LongEnum : long {
foo,
bar,
}
You can cast explicitly from and implicitly to the the base type, which is useful in switch-statements. Beware that one can cast any value of the base type to an enum, even if the enum has no member with the appropriate value. So usi...
Windows path in Python
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you can use always:
'C:/mydir'
this works both in linux and windows.
Other posibility is
'C:\\mydir'
if you have problems with some names you can also try raw string literals:
r'C:\mydir'
however best practice is to use the os.path module functions that always select the cor...