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What is a sealed trait?
...only extended in a single file, the compiler knows every possible subtypes and can reason about it.
For instance with the declaration:
sealed trait Answer
case object Yes extends Answer
case object No extends Answer
The compiler will emit a warning if a match is not exhaustive:
scala> val x:...
How can I return pivot table output in MySQL?
...w.artfulsoftware.com/infotree/qrytip.php?id=78
I advise reading this post and adapt this solution to your needs.
Update
After the link above is currently not available any longer I feel obliged to provide some additional information for all of you searching for mysql pivot answers in here. It rea...
Configuring diff tool with .gitconfig
...ld, xxdiff, emerge, vimdiff, gvimdiff, ecmerge, diffuse, opendiff, p4merge and araxis), and also allows you to specify your own. To use one of the pre-configured difftools (for example, "vimdiff"), you add the following lines to your ~/.gitconfig:
[diff]
tool = vimdiff
Now, you will be able t...
Build Android Studio app via command line
I want to build an Android Studio app (the Gradle build system), but I want to do this via the command line.
12 Answers
...
Amazon EC2, mysql aborting start because InnoDB: mmap (x bytes) failed; errno 12
.... Since Micro instances have only 613MB of memory, MySQL crashed every now and then. After a long search about MySQL, Micro Instance and Memory Managment I found out there is no default SWAP space for Micro instance. So if you want to avoid the crash you may need to setup a swap space for your micro...
List comprehension rebinds names even after scope of comprehension. Is this right?
...change in Python
3, to improve equivalence between list
comprehensions and generator
expressions. In Python 2, the list
comprehension "leaks" the loop control
variable into the surrounding scope:
x = 'before'
a = [x for x in 1, 2, 3]
print x # this prints '3', not 'before'
This was ...
How do you access a website running on localhost from iPhone browser
I am working on a mobile website and would like to test it using my iPhone browser. My Windows 7 machine and iPhone are on the same wireless network. How do I access localhost from the iPhone? Right now I get a 404 error.
...
Converting PKCS#12 certificate into PEM using OpenSSL
... in newfile.crt.pem
private key in newfile.key.pem
To put the certificate and key in the same file without a password, use the following, as an empty password will cause the key to not be exported:
openssl pkcs12 -in path.p12 -out newfile.pem -nodes
Or, if you want to provide a password for the pr...
How can I get the MAC and the IP address of a connected client in PHP?
I need to know the MAC and the IP address of the connect clients, how can I do this in PHP?
16 Answers
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Converting String to “Character” array in Java
...
I wish ArrayUtils is standard in JVMs!
– Alvin
Apr 4 '12 at 6:58
4
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