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Python exit commands - why so many and when should each be used?
It seems that python supports many different commands to stop script execution. The choices I've found are: quit() , exit() , sys.exit() , os._exit()
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How do you programmatically set an attribute?
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StackExchange.ifUsing("editor", function () {
StackExchange.using("externalEditor", function () {
StackExchange.using("snippets", function () {
StackExchange.snippets.init();
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Match multiple cases classes in scala
...> "A"
case B(_) | C(_) => "B"
case _ => "default"
}
}
If you must, must, must extract the parameter and treat them in the same code block, you could:
def matcher(l: Foo): String = {
l match {
case A() => "A"
case bOrC @ (B(_) | C(_)) => {
val s = bOrC.asIn...
What does the variable $this mean in PHP?
... created by the interpreter for you, that contains an array of variables.
If you call $this inside a normal method in a normal class, $this returns the Object (the class) to which that method belongs.
It's possible for $this to be undefined if the context has no parent Object.
php.net has a b...
UnmodifiableMap (Java Collections) vs ImmutableMap (Google) [duplicate]
... still possible:
realMap.put("E", "F");
// The change in the "realMap" is now also visible
// in the "unmodifiableMap". So the unmodifiableMap
// has changed after it has been created.
unmodifiableMap.get("E"); // Will return "F".
In contrast to that, the ImmutableMap of Guava is really immutabl...
Creating a blocking Queue in .NET?
...hreads adding to a queue and multiple threads reading from the same queue. If the queue reaches a specific size all threads that are filling the queue will be blocked on add until an item is removed from the queue.
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How do I install from a local cache with pip?
... downloaded and added to the PIP_DOWNLOAD_CACHE directory. For instance, I now have quite a few Django packages.
This doesn't remove the need for network access, as stated in the pip news, so it's not the answer for creating new virtualenvs on the airplane, but it's still great.
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How to get the last N rows of a pandas DataFrame?
...on or label:
df.iloc[-3:]
see the docs.
As Wes points out, in this specific case you should just use tail!
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Dynamically updating plot in matplotlib
... Since there is no call to show(), the plot never appears on the screen. If I call show(), it blocks and doesn't perform the updates. Am I missing something? gist.github.com/daviddoria/027b5c158b6f200527a4
– David Doria
Sep 18 '15 at 11:14
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What is the difference between tree depth and height?
... the next, and I'm posting this so everyone is aware that this discrepancy now exists and hopefully won't cause bugs in any programs! Thanks.
From the OpenDSA Data Structures & Algos book:
If n1, n2,...,nk is a sequence of nodes in the tree such
that ni is the parent of ni+1 for 1<=i...