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Is there a Unix utility to prepend timestamps to stdin?
...row this out there: there are a pair of utilities in daemontools called tai64n and tai64nlocal that are made for prepending timestamps to log messages.
Example:
cat file | tai64n | tai64nlocal
Integer division with remainder in JavaScript?
...8 millisec
(a-(a%b))/b // -33, 0.6649 millisec
The above is based on 10 million trials for each.
Conclusion: Use (a/b>>0) (or (~~(a/b)) or (a/b|0)) to achieve about 20% gain in efficiency. Also keep in mind that they are all inconsistent with Math.floor, when a/b<0 &&...
How to add custom method to Spring Data JPA
...e final AccountRepositoryBasic accountRepositoryBasic;
// constructor-based injection
public AccountRepositoryCustomImpl(
AccountRepositoryBasic accountRepositoryBasic)
{
this.accountRepositoryBasic = accountRepositoryBasic;
}
public void customMethod()
{
...
C/C++中的段错误（Segmentation fault） - C/C++ - 清泛网 - 专注C/C++及内核技术
...read-only location, or to overwrite part of the operating system). Systems based on processors like the Motorola 68000 tend to refer to these events as Address or Bus errors.
Segmentation is one approach to memory management and protection in the operating system. It has been superseded by pagi...
Are there disadvantages to using a generic varchar(255) for all text-based fields?
...hat in practice stored very short strings.
It's best to define the column based on the type of data that you intend to store. It has benefits to enforce application-related constraints, as other folks have mentioned. But it has the physical benefits to avoid the memory waste I described above.
I...
Why should hash functions use a prime number modulus?
...a safe assumption. But you can still get occasional bad hashing behaviours based on hash functions like the one above, and prime bucket count could help further.
Putting about the principle that "everything has to be prime" is as far as I know a sufficient but not a necessary condition for good dis...
What's the hardest or most misunderstood aspect of LINQ? [closed]
... like to know which topics are worth giving a fair amount of attention to, based on what people may find hard to understand, or what they may have a mistaken impression of. I won't be specifically talking about LINQ to SQL or the Entity Framework except as examples of how queries can be executed...
What's the difference between emulation and simulation? [duplicate]
...
Based on software and system engineering experience, I'd summarise the difference as follows:
Simulation: for me, this is always in software - every aspect of the real system is only MODELLED by some code and/or mathematics....
Normalizing mousewheel speed across browsers
...cannot be detected by JS
…I can only recommend using this simple, sign-based-counting code:
var handleScroll = function(evt){
if (!evt) evt = event;
var direction = (evt.detail<0 || evt.wheelDelta>0) ? 1 : -1;
// Use the value as you will
};
someEl.addEventListener('DOMMouseScroll',...
What is a NullReferenceException, and how do I fix it?
...Note that C# has the concept of nullable datatypes for variables (like database tables can have nullable fields) - you can assign null to them to indicate there is no value stored in it, for example int? a = null; where the question mark indicates it is allowed to store null in variable a. You can c...