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Why use Abstract Base Classes in Python?
...emented classes.
Long version
There is a contract between a class and its callers. The class promises to do certain things and have certain properties.
There are different levels to the contract.
At a very low level, the contract might include the name of a method or its number of parameters.
In a s...
Installing older version of R package
...
To install an older version of a package from source (within R):
packageurl <- "http://cran.r-project.org/src/contrib/Archive/ggplot2/ggplot2_0.9.1.tar.gz"
install.packages(packageurl, repos=NULL, type="source")
If this doesn'...
What is a singleton in C#?
...
A singleton is a class which only allows one instance of itself to be created - and gives simple, easy access to said instance. The singleton premise is a pattern across software development.
There is a C# implementation "Implementing the Singleton Pattern i...
How to count total lines changed by a specific author in a Git repository?
...--author="<authorname>" --oneline --shortstat
This gives stats for all commits on the current HEAD. If you want to add up stats in other branches you will have to supply them as arguments to git log.
For passing to a script, removing even the "oneline" format can be done with an empty log f...
Iterating over Java collections in Scala
...
As of Scala 2.8, all you have to do is to import the JavaConversions object, which already declares the appropriate conversions.
import scala.collection.JavaConversions._
This won't work in previous versions though.
...
How do I provide custom cast support for my class?
...ou want users to have to cast it or whether you want it to happen automagically. Generally, one direction will always work, that's where you use implicit, and the other direction can sometimes fail, that's where you use explicit.
The syntax is like this:
public static implicit operator dbInt64(Byt...
Simplest/Cleanest way to implement singleton in JavaScript?
...
return { // public interface
publicMethod1: function () {
// all private members are accessible here
},
publicMethod2: function () {
}
};
})();
This has been called the module pattern, it basically allows you to encapsulate private members on an object, by taking advant...
Django MEDIA_URL and MEDIA_ROOT
... answer below; it is a better solution.
– Thane Brimhall
Apr 6 '16 at 14:14
is this in your app or project urls.py?
...
Changing password with Oracle SQL Developer
... answered Feb 4 '13 at 22:21
NiallNiall
1,06911 gold badge77 silver badges33 bronze badges
...
How do I find the duplicates in a list and create another list with them?
... @Hugo, to see the list of duplicates, we just need to create a new list called dup and add an else statement. For example: dup = [] else: dup.append(x)
– Chris Nielsen
Apr 29 '16 at 16:45
...