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What does the caret operator (^) in Python do?
...his way:
1000 # 8 (binary)
0011 # 3 (binary)
---- # APPLY XOR ('vertically')
1011 # result = 11 (binary)
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MongoDB/Mongoose querying at a specific date?
...onents. To query those times you need to create a date range that includes all moments in a day.
db.posts.find( //query today up to tonight
{"created_on": {"$gte": new Date(2012, 7, 14), "$lt": new Date(2012, 7, 15)}})
s...
Does use of final keyword in Java improve the performance?
...
Usually not. For virtual methods, HotSpot keeps track of whether the method has actually been overridden, and is able to perform optimizations such as inlining on the assumption that a method hasn't been overridden - until it lo...
Why isn't sizeof for a struct equal to the sum of sizeof of each member?
... errors.
Here's an example using typical settings for an x86 processor (all used 32 and 64 bit modes):
struct X
{
short s; /* 2 bytes */
/* 2 padding bytes */
int i; /* 4 bytes */
char c; /* 1 byte */
/* 3 padding bytes */
};
struct Y
{
int i; /* 4...
What are C++ functors and their uses?
...42); // create an instance of the functor class
int i = add42(8); // and "call" it
assert(i == 50); // and it added 42 to its argument
std::vector<int> in; // assume this contains a bunch of values)
std::vector<int> out(in.size());
// Pass a functor to std::transform, which calls the fu...
Scala how can I count the number of occurrences in a list
...", "banana", "apple", "oranges", "oranges")
s.groupBy(identity).mapValues(_.size)
giving a Map with a count for each item in the original sequence:
Map(banana -> 1, oranges -> 3, apple -> 3)
The question asks how to find the count of a specific item. With this approach, the solution w...
Lua简明教程 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...ble来管理全局变量的，Lua把这些全局变量放在了一个叫“_G”的Table里。
我们可以用如下的方式来访问一个全局变量（假设我们这个全局变量名叫globalVar）：
1
2
_G.globalVar
_G["globalVar"]
我们可...
How to make a python, command-line program autocomplete arbitrary things NOT interpreter
...ts, i.e. --help, --verbose and --version. For your purposes, you'll essentially want to customise the values that are put into opts.
Do have a look at the example on the linked page, it's all pretty straightforward.
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Convert string to binary in python
...encoding.
In Python 3, then, you can do something like this:
a = "test"
a_bytes = bytes(a, "ascii")
print(' '.join(["{0:b}".format(x) for x in a_bytes]))
The differences between UTF-8 and ascii encoding won't be obvious for simple alphanumeric strings, but will become important if you're process...
How to Apply Gradient to background view of iOS Swift App
...ems you may face with this is that when you add a sublayer it may sit over all your other items, labels, image, etc. To overcome this create another view that sits below everything and set its constraints to that of the container you want the gradient in. Then set the gradient to be applied to this ...