大约有 15,400 项符合查询结果（耗时：0.0230秒） [XML]
Select first 4 rows of a data.frame in R
...
Use head:
dnow <- data.frame(x=rnorm(100), y=runif(100))
head(dnow,4) ## default is 6
share
|
improve this answer
|
follow
...
How to perform case-insensitive sorting in JavaScript?
...yet supported on all platforms/browsers. I know they are not used in this example, but just wanted to add for clarity. See MDN for more info
– Ayame__
Jan 9 '14 at 15:05
105
...
Why can't I reference System.ComponentModel.DataAnnotations?
I'm trying to use DataAnnotations in my WPF project to specify a maximum length of strings, with the following:
14 Answers
...
Import CSV to SQLite
...
@d33tah Look at these examples. Notice how the first line contains the column names Year,Make,Model,Description,Price and not actual data. If that's the case with your CSV file, then you do not need to manually create the table using the create tab...
Remove array element based on object property
...
Note that filter() is only available for Internet Explorer 9+
– jessegavin
Apr 29 '13 at 14:51
...
Git serve: I would like it that simple
...ublish over http = much like Mercurial 's hg serve! On the Windows/work box do this:
8 Answers
...
How do I run only specific tests in Rspec?
...
It isn't easy to find the documentation, but you can tag examples with a hash. Eg.
# spec/my_spec.rb
describe SomeContext do
it "won't run this" do
raise "never reached"
end
it "will run this", :focus => true do
1.should == 1
end
end
$ rspec --tag focus spec/my...
Convert dd-mm-yyyy string to date
...val().split("-")
var f = new Date(from[2], from[1] - 1, from[0])
Use regex
var date = new Date("15-05-2018".replace( /(\d{2})-(\d{2})-(\d{4})/, "$2/$1/$3"))
Why not use regex?
Because you know you'll be working on a string made up of three parts, separated by hyphens.
However, if you were loo...
Adding a Google Plus (one or share) link to an email newsletter
...
https://plus.google.com/share?url=http%3A%2F%2Fexample.com
You can share the link on Google+ with the official Google+ share link.
Replace the url parameter with the URL encoded link you want to share.
...
How to uninstall Jenkins?
...led using the official Jenkins Mac installer from http://jenkins-ci.org/
Execute uninstall script from terminal:
'/Library/Application Support/Jenkins/Uninstall.command'
or use Finder to navigate into that folder and double-click on Uninstall.command.
Finally delete last configuration bits whic...