大约有 15,000 项符合查询结果（耗时：0.0343秒） [XML]
Why are preprocessor macros evil and what are the alternatives?
...fect tool.
There are a few aspects to macros that make them "bad" (I'll expand on each later, and suggest alternatives):
You can not debug macros.
Macro expansion can lead to strange side effects.
Macros have no "namespace", so if you have a macro that clashes with a name used elsewhere, you ge...
Plot two graphs in same plot in R
...
lines() or points() will add to the existing graph, but will not create a new window. So you'd need to do
plot(x,y1,type="l",col="red")
lines(x,y2,col="green")
share
|
...
Why are regular expressions so controversial? [closed]
When exploring regular expressions (otherwise known as RegEx-es), there are many individuals who seem to see regular expressions as the Holy Grail. Something that looks so complicated - just must be the answer to any question. They tend to think that every problem is solvable using regular express...
Why is `std::move` named `std::move`?
The C++11 std::move(x) function doesn't really move anything at all. It is just a cast to r-value. Why was this done? Isn't this misleading?
...
Find an element in a list of tuples
...each tuple is 2: you can convert your list into a single dictionary.
For example,
test = [("hi", 1), ("there", 2)]
test = dict(test)
print test["hi"] # prints 1
share
|
improve this answer
...
Best practices for circular shift (rotate) operations in C++
...otate question with some more details about what asm gcc/clang produce for x86.
The most compiler-friendly way to express a rotate in C and C++ that avoids any Undefined Behaviour seems to be John Regehr's implementation. I've adapted it to rotate by the width of the type (using fixed-width types ...
Understanding the map function
...omprehensions instead:
map(f, iterable)
is basically equivalent to:
[f(x) for x in iterable]
map on its own can't do a Cartesian product, because the length of its output list is always the same as its input list. You can trivially do a Cartesian product with a list comprehension though:
[(a,...
How to remove ASP.Net MVC Default HTTP Headers?
...
X-Powered-By is a custom header in IIS. Since IIS 7, you can remove it by adding the following to your web.config:
<system.webServer>
<httpProtocol>
<customHeaders>
<remove name="X-Powered-By...
Can a for loop increment/decrement by more than one?
...ways to increment a for loop in Javascript besides i++ and ++i ? For example, I want to increment by 3 instead of one.
...
Passing an integer by reference in Python
...nd is to pass the integer in a container which can be mutated:
def change(x):
x[0] = 3
x = [1]
change(x)
print x
This is ugly/clumsy at best, but you're not going to do any better in Python. The reason is because in Python, assignment (=) takes whatever object is the result of the right hand...