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Scala type programming resources
...ample (taken from metascala and apocalisp):
sealed trait Nat
sealed trait _0 extends Nat
sealed trait Succ[N <: Nat] extends Nat
Here you have a peano encoding of the natural numbers. That is, you have a type for each non-negative integer: a special type for 0, namely _0; and each integer grea...
How are Python's Built In Dictionaries Implemented?
...keys' hashes. You can think of it like this:
hash key dict_0 dict_1 dict_2...
...010001 ffeb678c 633241c4 fffad420 ...
... ... ... ... ...
For a 64 bit machine, this could save up to 16 bytes per key per extra dictionary.
Shared Keys for...
How can I time a code segment for testing performance with Pythons timeit?
...e and after the block you want to time.
import time
t0 = time.time()
code_block
t1 = time.time()
total = t1-t0
This method is not as exact as timeit (it does not average several runs) but it is straightforward.
time.time() (in Windows and Linux) and time.clock() (in Linux) are not precise eno...
Regular Expression for alphanumeric and underscores
...that contains only those characters (or an empty string), try
"^[a-zA-Z0-9_]*$"
This works for .NET regular expressions, and probably a lot of other languages as well.
Breaking it down:
^ : start of string
[ : beginning of character group
a-z : any lowercase letter
A-Z : any uppercase letter
0-...
Convert all first letter to upper case, rest lower for each word
....Thread.CurrentThread.CurrentCulture.TextInfo.ToTitleCase(s.ToLower());
IL_0000: ldstr "THIS IS MY TEXT RIGHT NOW"
IL_0005: stloc.0 // s
IL_0006: call System.Threading.Thread.get_CurrentThread
IL_000B: callvirt System.Threading.Thread.get_CurrentCulture
IL_0010: callvirt ...
Scala: List[Future] to Future[List] disregarding failed futures
...
def futureToFutureTry[T](f: Future[T]): Future[Try[T]] =
f.map(Success(_)).recover { case x => Failure(x)}
val listOfFutures = ...
val listOfFutureTrys = listOfFutures.map(futureToFutureTry(_))
Then use Future.sequence as before, to give you a Future[List[Try[T]]]
val futureListOfTrys = F...
How do I log a Python error with debug information?
...
The exception method simply calls error(message, exc_info=1). As soon as you pass exc_info to any of the logging methods from an exception context, you will get a traceback.
– Helmut Grohne
Jun 25 '13 at 18:46
...
Using the Underscore module with Node.js
...ms that the first time I use a function from Underscore, it overwrites the _ object with the result of my function call. Anyone know what's going on? For example, here is a session from the node.js REPL:
...
Why is using 'eval' a bad practice?
..."
attsToStore=('Name', 'Artist', 'Album', 'Genre', 'Location')
def __init__(self):
for att in self.attsToStore:
setattr(self, att.lower(), None)
def setDetail(self, key, val):
if key in self.attsToStore:
setattr(self, key.lower(), val)
EDIT:
The...
How to determine the version of the C++ standard used by the compiler?
...ngs:
/*Define Microsoft Visual C++ .NET (32-bit) compiler */
#if (defined(_M_IX86) && defined(_MSC_VER) && (_MSC_VER >= 1300)
...
#endif
/*Define Borland 5.0 C++ (16-bit) compiler */
#if defined(__BORLANDC__) && !defined(__WIN32__)
...
#endif
You probably wil...