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When NOT to use yield (return) [duplicate]
...res. For example, I often see this:
public static IEnumerable<T> PreorderTraversal<T>(Tree<T> root)
{
if (root == null) yield break;
yield return root.Value;
foreach(T item in PreorderTraversal(root.Left))
yield return item;
foreach(T item in PreorderTraver...
How do I concatenate two text files in PowerShell?
...
For me the cat command runs multiple orders of magnitude longer than the cmd /c command (which runs really quick); thanks for pointing out the option!
– Rob
Aug 13 '14 at 12:23
...
ALTER TABLE to add a composite primary key
...t it after you recreate the primary key.
Also, when using composite keys, order is important.
These
1) ALTER TABLE provider ADD PRIMARY KEY(person,place,thing);
and
2) ALTER TABLE provider ADD PRIMARY KEY(person,thing,place);
are not the the same thing.
They both enforce uniqueness on that set ...
StringIO in Python3
...
In order to make examples from here
work with Python 3.5.2, you can rewrite as follows :
import io
data =io.BytesIO(b"1, 2, 3\n4, 5, 6")
import numpy
numpy.genfromtxt(data, delimiter=",")
The reason for the change may be tha...
Can I create a One-Time-Use Function in a Script or Stored Procedure?
...That is not function within a script and may still require permissions. In order to avoid repetitive segments the only option SQL has is WITH statement.
– alex.peter
Dec 6 '19 at 17:38
...
How to design a multi-user ajax web application to be concurrently safe
...r cruel to your infrastructure if you do not configure your (Apache?) and (php?) well enough to be "lightweight" starters. It is desirable to optimize the polling request on the serverside so that it runs for far less time than the length of the polling interval. Splitting that runtime in half might...
Why would one use nested classes in C++?
...lection and Element - bad, because the name "Element" is general enough in order to cause a possible name clash
introduce a namespace someSpecificCollection and declare classes someSpecificCollection::Collection and someSpecificCollection::Element. No risk of name clash, but can it get any more verb...
json.dumps vs flask.jsonify
...ication/json')
The json module used is either simplejson or json in that order. current_app is a reference to the Flask() object i.e. your application. response_class() is a reference to the Response() class.
share
...
Is it more efficient to copy a vector by reserving and copying, or by creating and swapping? [duplic
...structs a container with a copy of each of the elements in x , in the same order.
Caution:
Do not use std::vector::swap
std::vector::swap is not copying a vector to another, it is actually swapping elements of two vectors, just as its name suggests. In other words, the source vector to copy fr...
What's the difference between the atomic and nonatomic attributes?
...= userName_;
}
}
Basically, the atomic version has to take a lock in order to guarantee thread safety, and also is bumping the ref count on the object (and the autorelease count to balance it) so that the object is guaranteed to exist for the caller, otherwise there is a potential race conditi...