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Why does += behave unexpectedly on lists?
...
The general answer is that += tries to call the __iadd__ special method, and if that isn't available it tries to use __add__ instead. So the issue is with the difference between these special methods.
The __iadd__ special method is for an in-place addition, that is it mut...
Reference requirements.txt for the install_requires kwarg in setuptools setup.py file
...w is to list all dependencies in setup.py and remove requirements.txt. For applications requiring both, simply reduce the dependency list in requirements.txt to merely the . character. Done.
– Cecil Curry
Jun 30 '16 at 5:40
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What is the use of static variable in C#? When to use it? Why can't I declare the static variable in
...red. Let me explain this with an example:
class circle
{
public float _PI =3.14F;
public int Radius;
public funtionArea(int radius)
{
return this.radius * this._PI
}
}
class program
{
public static void main()
{
Circle c1 = new Cirle();
flo...
What tools are there for functional programming in C?
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FFCALL lets you build closures in C -- callback = alloc_callback(&function, data) returns a function pointer such that callback(arg1, ...) is equivalent to calling function(data, arg1, ...). You will have to handle garbage collection manually, though.
Relatedly, blocks have...
How do I read / convert an InputStream into a String in Java?
...Utils)
String result = IOUtils.toString(inputStream, StandardCharsets.UTF_8);
Using CharStreams (Guava)
String result = CharStreams.toString(new InputStreamReader(
inputStream, Charsets.UTF_8));
Using Scanner (JDK)
Scanner s = new Scanner(inputStream).useDelimiter("\\A");
String result...
Queue.Queue vs. collections.deque
...ly intended as a datastructure. That's why Queue.Queue has methods like put_nowait(), get_nowait(), and join(), whereas collections.deque doesn't. Queue.Queue isn't intended to be used as a collection, which is why it lacks the likes of the in operator.
It boils down to this: if you have multiple t...
How to return result of a SELECT inside a function in PostgreSQL?
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Use RETURN QUERY:
CREATE OR REPLACE FUNCTION word_frequency(_max_tokens int)
RETURNS TABLE (txt text -- also visible as OUT parameter inside function
, cnt bigint
, ratio bigint) AS
$func$
BEGIN
RETURN QUERY
SELECT t.txt
,...
SQL Server: Filter output of sp_who2
Under SQL Server, is there an easy way to filter the output of sp_who2? Say I wanted to just show rows for a certain database, for example.
...
VS Debug调试模式下内存泄露检测原理 - C/C++ - 清泛网 - 专注C/C++及内核技术
...T宏定义了malloc、realloc，如下：
#define malloc(s) _malloc_dbg(s, _NORMAL_BLOCK, __FILE__, __LINE__)
#define calloc(c, s) _calloc_dbg(c, s, _NORMAL_BLOCK, __FILE__, __LINE__)
#define realloc(p, s) _realloc_dbg(p, s, _NORMAL_BLOCK, __FILE__, __LINE__)
...
Why use Abstract Base Classes in Python?
...igher-level, semantic promises in the contract.
For example, if there is a __str__() method, it is expected to return a string representation of the object. It could delete all contents of the object, commit the transaction and spit a blank page out of the printer... but there is a common understand...