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system(“pause”); - Why is it wrong?
...nstead to get around a feature of the IDE/OS - the console window launched from Visual Studio closes when the program has finished execution, and so the new user doesn't get to see the output of his new program.
Bodging in System("pause") runs the Windows command-line "pause" program and waits for ...
open read and close a file in 1 line of code
...p", "copyright", "credits" or "license" for more information.
>>> from pathlib import Path
>>> (Path("/etc") / "hostname").read_text()
'dev1.example\n'
On Python 27 install backported pathlib or pathlib2
...
Why can't strings be mutable in Java and .NET?
...,
immutable objects can be shared freely
[...]
Other small points from the same chapter:
Not only can you share immutable objects, but you can share their internals.
[...]
Immutable objects make great building blocks for other objects, whether mutable or immutable.
[...]
...
How does push notification technology work on Android?
...
From what I've heard during an Android developers conference in Israel:
There is simply a TCP socket waiting in accept mode on a cloud Google server. The TCP connection had been initiated by the Google Play application. That...
How do you convert a time.struct_time object into a datetime object?
... time tuple (in localtime) into seconds since the Epoch, then use datetime.fromtimestamp() to get the datetime object.
from datetime import datetime
from time import mktime
dt = datetime.fromtimestamp(mktime(struct))
shar...
How do I find the caller of a method using stacktrace or reflection?
...{
return "Reflection";
}
}
/**
* Get a stack trace from the current thread
*/
private static class ThreadStackTraceMethod extends GetCallerClassNameMethod {
public String getCallerClassName(int callStackDepth) {
return Thread.currentThread().getStackTrac...
What is an idempotent operation?
...re than once with the same input parameters. For example, removing an item from a set can be considered an idempotent operation on the set.
In mathematics, an idempotent operation is one where f(f(x)) = f(x). For example, the abs() function is idempotent because abs(abs(x)) = abs(x) for all x.
Th...
What is the purpose of a stack? Why do we need it?
...d not the actual per-thread stack at runtime.
Why is there a transfer from memory to stack or "loading?" On the other hand, why is there a transfer from stack to memory or "storing"? Why not just have them all placed in the memory?
MSIL is a "virtual machine" language. Compilers like the C# c...
How do ACID and database transactions work?
...l ever be violated.
Isolation means that one transaction cannot read data from another transaction that is not yet completed. If two transactions are executing concurrently, each one will see the world as if they were executing sequentially, and if one needs to read data that is written by another,...
How to get the client IP address in PHP [duplicate]
...
Whatever you do, make sure not to trust data sent from the client. $_SERVER['REMOTE_ADDR'] contains the real IP address of the connecting party. That is the most reliable value you can find.
However, they can be behind a proxy server in which case the proxy may have set th...