Tutorial by Examples: ti

A class, functions as a template that defines the basic characteristics of a particular object. Here's an example: class Person(object): """A simple class.""" # docstring species = "Homo Sapiens" ...

By default the Large Object Heap is not compacted unlike the classic Object Heap which can lead to memory fragmentation and further, can lead to OutOfMemoryExceptions Starting with .NET 4.5.1 there is an option to explicitly compact the Large Object Heap (along with a garbage collection): GCSettin...

In Symfony it's possible to define multiple routes for one action. This can be very helpful if you have functions that do the same but have different parameters. class TestController extends Controller { /** * @Route("/test1/{id}", name="test") * @Route("/...

We can omit the argument in the call if that argument is an Optional Argument Every Optional Argument has its own default value It will take default value if we do not supply the value A default value of a Optional Argument must be a Constant expression. Must be a value type such as enum or s...

The ref keyword for callers of methods is now optional when calling into methods supplied by COM interfaces. Given a COM method with the signature void Increment(ref int x); the invocation can now be written as either Increment(0); // no need for "ref" or a place holder variable any m...

The IQueryable and IQueryable<T> interfaces allows developers to translate a LINQ query (a 'language-integrated' query) to a specific datasource, for example a relational database. Take this LINQ query written in C#: var query = from book in books where book.Author == "Steph...

XML <Galaxy> <Light>sun</Light> <Device>satellite</Device> <Sensor>human</Sensor> <Name>Milky Way</Name> </Galaxy> XPATH /Galaxy/*[lower-case(local-name())="light"] or //*[lower-case(local-name())=&qu...

To create a function which accepts an undetermined number of arguments, there are two methods depending on your environment. 5 Whenever a function is called, it has an Array-like arguments object in its scope, containing all the arguments passed to the function. Indexing into or iterating over th...

XML <Galaxy> <name>Milky Way</name> <CelestialObject name="Earth" type="planet"/> <CelestialObject name="Sun" type="star"/> </Galaxy> XPATH /Galaxy/*[contains(lower-case(@name),'ear')] or //*[contain...

To POST a JSON body, pass in a Python data structure to the json argument; here a dictionary is posted but anything that can be encoded to JSON will do: import requests # Create a dictionary to be sent. json_data = {'foo': ['bar', 'baz'], 'spam': True, 'eggs': 5.5} # Send the data. response...

Conditional contexts in Lua (if, elseif, while, until) do not require a boolean. Like many languages, any Lua value can appear in a condition. The rules for evaluation are simple: false and nil count as false. Everything else counts as true. if 1 then print("Numbers work.") ...

Declaration A common misunderstanding, especially beginners, have is read-only property is the one marked with readonly keyword. That's not correct and in fact following is a compile time error: public readonly string SomeProp { get; set; } A property is read-only when it only has a getter. pu...

K&R void* is a catch all type for pointers to object types. An example of this in use is with the malloc function, which is declared as void* malloc(size_t); The pointer-to-void return type means that it is possible to assign the return value from malloc to a pointer to any other type of ob...

Conditional expressions can be done with ~[ and ~]. The clauses of the expression are separated using ~;. By default, ~[ takes an integer from the argument list, and picks the corresponding clause. The clauses start at zero. (format t "~@{~[First clause~;Second clause~;Third clause~;Fourth cl...

Schema Statics are methods that can be invoked directly by a Model (unlike Schema Methods, which need to be invoked by an instance of a Mongoose document). You assign a Static to a schema by adding the function to the schema's statics object. One example use case is for constructing custom queries:...

A Set is a Collection that cannot contain duplicate elements. It models the mathematical set abstraction. Set have its implementation in various classes like HashSet, TreeSet, LinkedHashSet. For example: HashSet: Set<T> set = new HashSet<T>(); Here T can be String, Integer or any ...

+ dictionaryWithCapacity: Creates and returns a mutable dictionary, initially giving it enough allocated memory to hold a given number of entries. NSMutableDictionary *dict = [NSMutableDictionary dictionaryWithCapacity:1]; NSLog(@"%@",dict); - init Initializes a newly allocated mut...

- removeObjectForKey: Removes a given key and its associated value from the dictionary. NSMutableDictionary *dict = [NSMutableDictionary dictionaryWithDictionary:@{@"key1":@"Easy",@"key2": @"Tutorials"}]; [dict removeObjectForKey:@"key1"]; NSLog...

A declaration introduces an identifier and describes its type, be it a type, object, or function. A declaration is what the compiler needs to accept references to that identifier. These are declarations: extern int bar; extern int g(int, int); double f(int, double); /* extern can be omitted for f...

When writing a copy assignment operator, it is very important that it be able to work in the event of self-assignment. That is, it has to allow this: SomeType t = ...; t = t; Self-assignment usually doesn't happen in such an obvious way. It typically happens via a circuitous route through vario...