大约有 40,810 项符合查询结果（耗时：0.1092秒） [XML]
Standardize data columns in R
... function on the data to do what you want.
dat <- data.frame(x = rnorm(10, 30, .2), y = runif(10, 3, 5))
scaled.dat <- scale(dat)
# check that we get mean of 0 and sd of 1
colMeans(scaled.dat) # faster version of apply(scaled.dat, 2, mean)
apply(scaled.dat, 2, sd)
Using built in functions...
Named regular expression group “(?Pregexp)”: what does “P” stand for?
...ions
From: Guido van Rossum (gui...@CNRI.Reston.Va.US)
Date: Dec 10, 1997 3:36:19 pm
I have an unusual request for the Perl developers (those that develop
the Perl language). I hope this (perl5-porters) is the right list. I
am cc'ing the Python string-sig because it is the origi...
Is using 'var' to declare variables optional? [duplicate]
...
answered Mar 21 '10 at 1:10
Stefano BoriniStefano Borini
120k8181 gold badges267267 silver badges395395 bronze badges
...
How is “mvn clean install” different from “mvn install”?
...
Andreas DolkAndreas Dolk
106k1515 gold badges165165 silver badges247247 bronze badges
...
Difference between os.getenv and os.environ.get
... |
edited May 23 '17 at 10:31
Community♦
111 silver badge
answered Jun 4 '13 at 18:04
...
What is the entry point of swift code execution?
...
answered May 4 at 10:48
Bartosz OlszanowskiBartosz Olszanowski
48666 silver badges99 bronze badges
...
What is the performance of Objects/Arrays in JavaScript? (specifically for Google V8)
...
+100
I created a test suite, precisely to explore these issues (and more) (archived copy).
And in that sense, you can see the performanc...
difference between use and require
...
102
require loads libs (that aren't already loaded), use does the same plus it refers to their nam...
LINQ to SQL - Left Outer Join with multiple join conditions
...in fg.Where(f => f.otherid == 17).DefaultIfEmpty()
where p.companyid == 100
select f.value
Or you could use a subquery:
from p in context.Periods
join f in context.Facts on p.id equals f.periodid into fg
from fgi in (from f in fg
where f.otherid == 17
select f).Defaul...