大约有 47,000 项符合查询结果（耗时：0.0678秒） [XML]
dplyr summarise: Equivalent of “.drop=FALSE” to keep groups with zero length in output
When using summarise with plyr 's ddply function, empty categories are dropped by default. You can change this behavior by adding .drop = FALSE . However, this doesn't work when using summarise with dplyr . Is there another way to keep empty categories in the result?
...
How to connect to Mysql Server inside VirtualBox Vagrant?
I mounted a new VirtualBox Machine with Vagrant, and inside that VM I installed Mysql Server. How can I connect to that server outside the vm? I already forward the port 3306 of the Vagrantfile , but when I try to connect to the mysql server, it`s resposts with the error:
'reading initial communica...
How to convert ASCII code (0-255) to its corresponding character?
How can I convert, in Java, the ASCII code (which is an integer from [0, 255] range) to its corresponding ASCII character?
...
How to change colors of a Drawable in Android?
I'm working on an android application, and I have a drawable that I'm loading up from a source image. On this image, I'd like to convert all of the white pixels to a different color, say blue, and then cache the resultant Drawable object so I can use it later.
...
How to overcome TypeError: unhashable type: 'list'
I'm trying to take a file that looks like this:
6 Answers
6
...
Possible reasons for timeout when trying to access EC2 instance
I cannot SSH into my instance - Operation timed out. What could be the reasons why, and what can I do to resolve it? Rebooting normally takes a long time to take effect, and might just makes things worst
...
add a string prefix to each value in a string column using Pandas
I would like to append a string to the start of each value in a said column of a pandas dataframe (elegantly).
I already figured out how to kind-of do this and I am currently using:
...
ActiveRecord: size vs count
In Rails, you can find the number of records using both Model.size and Model.count . If you're dealing with more complex queries is there any advantage to using one method over the other? How are they different?
...
How to change line width in ggplot?
Datalink:
the data used
5 Answers
5
...
Catching error codes in a shell pipe
I currently have a script that does something like
4 Answers
4
...