大约有 40,000 项符合查询结果（耗时：0.0563秒） [XML]
Standardize data columns in R
...
z = runif(10, 10, 20))
dat
dat2 <- dat %>% mutate_at(c("y", "z"), ~(scale(.) %>% as.vector))
dat2
which gives me this:
> dat
x y z
1 29.75859 3.633225 14.56091
2 30.05549 3.605387 12.65187
3 30.21689 3.318092 13.04672
4 29.53086 3.079992...
What should my Objective-C singleton look like? [closed]
... below, I think you should be doing:
+ (id)sharedFoo
{
static dispatch_once_t once;
static MyFoo *sharedFoo;
dispatch_once(&once, ^ { sharedFoo = [[self alloc] init]; });
return sharedFoo;
}
share
...
Make sure only a single instance of a program is running
...bugs here.
You can install tend using one of the following methods:
easy_install tendo
pip install tendo
manually by getting it from http://pypi.python.org/pypi/tendo
share
|
improve this answer...
Can I access constants in settings.py from templates in Django?
..., frequently-used settings constants to the template such as settings.MEDIA_URL and some of the language settings if you use django's built in generic views or pass in a context instance keyword argument in the render_to_response shortcut function. Here's an example of each case:
from django.short...
Are tuples more efficient than lists in Python?
...2]
...
>>> import dis
>>> dis.dis(a)
2 0 LOAD_CONST 1 (1)
3 LOAD_CONST 2 (2)
6 LOAD_CONST 3 (3)
9 LOAD_CONST 4 (4)
12 LOAD_CONST 5 (5)
...
How to include JavaScript file or library in Chrome console?
...s answer, I wrapped it around a JS function and use it as follows ... var _loadScript = function(path){ var script= document.createElement('script'); script.type= 'text/javascript'; script.src= path; document.head.appendChild(script); } _loadScript('documentcloud.github.com/underscore/undersco...
Troubleshooting “Illegal mix of collations” error in mysql
...ERE clause will always give the error you posted:
WHERE 'A' COLLATE latin1_general_ci = 'A' COLLATE latin1_general_cs
Your solution is to specify a shared collation for the two columns within the query. Here is an example that uses the COLLATE clause:
SELECT * FROM table ORDER BY key COLLATE lat...
What is the Scala annotation to ensure a tail recursive function is optimized?
...e to Scala version 2.8.0.RC5 (Java HotSpot(TM) 64-Bit Server VM, Java 1.6.0_18).
Type in expressions to have them evaluated.
Type :help for more information.
scala> import scala.annotation.tailrec
import scala.annotation.tailrec
scala> class Tails {
| @tailrec def boom(x: Int): Int = {
...
unit testing of private functions with mocha and node.js
...r. One way to get around it now is to use module.exports = process.env.NODE_ENV === 'production' ? require('prod.js') : require('dev.js') and store your es6 code differences in those respective files.
– cchamberlain
Jun 1 '16 at 1:51
...
Get file name from URL
...
If you let String url = new URL(original_url).getPath() and add a special case for filenames that don't contain a . then this works fine.
– Jason C
May 6 '15 at 20:28
...