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TypeScript static classes
...hat cannot be subclassed and must contain only static methods. C# does not allow one to define functions outside of classes. In TypeScript this is possible, however.
If you're looking for a way to put your functions/methods in a namespace (i.e. not global), you could consider using TypeScript's mod...
How do I use valgrind to find memory leaks?
...o come to this question and are still new to Linux—you might have to install Valgrind on your system.
sudo apt install valgrind # Ubuntu, Debian, etc.
sudo yum install valgrind # RHEL, CentOS, Fedora, etc.
Valgrind is readily usable for C/C++ code, but can even be used for other
languages wh...
Objective-C declared @property attributes (nonatomic, copy, strong, weak)
... retaining the copy.
Assign
Assign is somewhat the opposite to copy. When calling the getter of an assign property, it returns a reference to the actual data. Typically you use this attribute when you have a property of primitive type (float, int, BOOL...)
Retain
retain is required when the attribut...
What does a colon following a C++ constructor name do? [duplicate]
...ctor's signature is:
MyClass();
This means that the constructor can be called with no parameters. This makes it a default constructor, i.e., one which will be called by default when you write MyClass someObject;.
The part : m_classID(-1), m_userdata(0) is called initialization list. It is a way...
Printing without newline (print 'a',) prints a space, how to remove?
... This will consume a bit of memory for the string, but only make a single call to print. Note that string concatenation using += is now linear in the size of the string you're concatenating so this will be fast.
>>> for i in xrange(20):
... s += 'a'
...
>>> print s
aaaaaaaaaa...
When should I use the Visitor Design Pattern? [closed]
...want to make the fewest possible modifications to it.
The Visitor pattern allows you to move each new operation in a suitable class, and you need to extend the hierarchy's interface only once. Let's do it. First, we define an abstract operation (the "Visitor" class in GoF) which has a method for ev...
Django rest framework nested self-referential objects
... the `subcategories` field
return CategorySerializer()
Actually, as you've noted the above isn't quite right.
This is a bit of a hack, but you might try adding the field in after the serializer is already declared.
class CategorySerializer(serializers.ModelSerializer):
parentCat...
Assignment inside lambda expression in Python
I have a list of objects and I want to remove all objects that are empty except for one, using filter and a lambda expression.
...
How to delete or add column in SQLITE?
...upports a limited subset of ALTER TABLE. The ALTER TABLE command in SQLite allows the user to rename a table or to add a new column to an existing table. It is not possible to rename a column, remove a column, or add or remove constraints from a table.
You can:
create new table as the one you ar...
How do you round a floating point number in Perl?
.... For rounding to a certain number of digits, sprintf() or printf() is usually the easiest
route.
printf("%.3f", 3.1415926535); # prints 3.142
The POSIX module (part of the standard Perl distribution) implements
ceil(), floor(), and a number of other mathematical and trigonometric
func...