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data.table vs dplyr: can one do something well the other can't or does poorly?
...operations together, it allows to easily optimise operations for speed and more importantly memory usage, and also provide some powerful features, all while maintaining the consistency in syntax.
1. Speed
Quite a few benchmarks (though mostly on grouping operations) have been added to the question...
How can I transform between the two styles of public key format, one “BEGIN RSA PUBLIC KEY”, the oth
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What is move semantics?
... denote temporary objects which are destroyed at the next semicolon (to be more precise: at the end of the full-expression that lexically contains the rvalue). This is important because during the initialization of b and c, we could do whatever we wanted with the source string, and the client couldn...
The definitive guide to form-based website authentication [closed]
...alt with the hash already. Check out this article on sec.stackexchange for more detailed information.
The reason a salt is used is that hashing in itself is not sufficient -- you'll want to add a so-called 'salt' to protect the hash against rainbow tables. A salt effectively prevents two passwords t...
Why does modern Perl avoid UTF-8 by default?
...nally useful in some sort of rare and isolated case. Unicode is much much more than just a larger character repertoire; it’s also how those characters all interact in many, many ways.
Even the simple-minded minimal measures that (some) people seem to think they want are guaranteed to miserably b...
【内核源码】linux UDP实现 - 操作系统(内核) - 清泛网 - 专注C/C++及内核技术
...plite = IS_UDPLITE(sk);
int corkreq = up->corkflag || msg->msg_flags&MSG_MORE; //UDP_CORK或者MSG_MORE
int (*getfrag)(void *, char *, int, int, int, struct sk_buff *);
struct sk_buff *skb;
struct ip_options_data opt_copy;
if (len > 0xFFFF) //长度不能超过64k， UDP头部只有16位...
API pagination best practices
...mically determined using the last data item in the list. This seems to be more or less how Facebook paginates in its Graph API (scroll down to the bottom to see the pagination links in the format I gave above).
One problem may be if you add a data item, but based on your description it sounds like...
Remove leading comma from a string
...e first character you would use:
var myOriginalString = ",'first string','more','even more'";
var myString = myOriginalString.substring(1);
I'm not sure this will be the result you're looking for though because you will still need to split it to create an array with it. Maybe something like:
va...
Multithreading: What is the point of more threads than cores?
... In that case, if you have a quad-core machine, what's the point of having more than 4 threads running at a time? Wouldn't they just be stealing time (CPU Resources) from each other?
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Is duplicated code more tolerable in unit tests?
...t tests some time ago when I went through and refactored them to make them more DRY --the intent of each test was no longer clear. It seems there is a trade-off between tests' readability and maintainability. If I leave duplicated code in unit tests, they're more readable, but then if I change th...