大约有 47,000 项符合查询结果（耗时：0.0566秒） [XML]
Should I use a data.frame or a matrix?
...he arguments of these functions determine the choice.
Also:
Matrices are more memory efficient:
m = matrix(1:4, 2, 2)
d = as.data.frame(m)
object.size(m)
# 216 bytes
object.size(d)
# 792 bytes
Matrices are a necessity if you plan to do any linear algebra-type of operations.
Data frames are mor...
Generate a random point within a circle (uniformly)
...here. That gives a direction. Now use random()+random()+random() with some more complex folding (ie. a 6-way fold of an infinitesimally thin parallelepiped to a terahedron). Not convinced this is a good method though.
– sigfpe
May 4 '11 at 17:52
...
Is memcached a dinosaur in comparison to Redis? [closed]
...y I saw bonded ethernet, across 4 ports. 4 x 44MB/s. This makes ram even more valuable, assuming you can get bonded ethernet going!
– Daniel
Jul 2 '11 at 1:59
1
...
MySQL vs PostgreSQL for Web Applications [closed]
...ython (Django) and would like to know whether MySQL or PostgreSQL would be more suitable when deploying for production.
10...
What does Google Closure Library offer over jQuery? [closed]
...
I'll try to add my piece of information.
More than another JS lib
As I understand it, Google Closure is not only another JS library, but it is also a set of tools that will allow you to optimize your JS code. Working with jQuery gives you good tools and a lightweig...
Why is it not advisable to have the database and web server on the same machine?
... of two servers (extra cost, dedicated network connection between the two, more maintenance, etc.), especially for a small application, where neither piece is using too much CPU or memory? Even with two servers, with one server compromised, an attacker could still do serious damage, either by delet...
How Do I Choose Between a Hash Table and a Trie (Prefix Tree)?
...n tries for most purposes.
Your keys need not have any special structure.
More space-efficient than the obvious linked trie structure (see comments below)
share
|
improve this answer
|
...
Cosmic Rays: what is the probability they will affect a program?
...ror checking can help to reduce the aftermath of failure. Also, because of more compact size of chips as commented by Joe, the failure rate could be different from what it was 20 years ago.
share
|
...
StringBuilder vs String concatenation in toString() in Java
...in fact turn it into version 2 - no performance difference whatsoever.
More importantly given we have only 3
properties it might not make a
difference, but at what point do you
switch from concat to builder?
At the point where you're concatenating in a loop - that's usually when the comp...