Tutorial by Examples: me

The requests module has top-level functions for most HTTP methods: r = requests.put('https://example.com/', data=put_body) r = requests.delete('https://example.com/') r = requests.head('https://example.com/') r = requests.options('https://example.com/') r = requests.patch('https://example.com/'...

Docker volumes are not automatically removed when a container is stopped. To remove associated volumes when you stop a container: docker rm -v <container id or name> If the -v flag is not specified, the volume remains on-disk as a 'dangling volume'. To delete all dangling volumes: docker ...

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...

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...

We can also use macros for making code easier to read and write. For example we can implement macros for implementing the foreach construct in C for some data structures like singly- and doubly-linked lists, queues, etc. Here is a small example. #include <stdio.h> #include <stdlib.h>...

You can retrieve the implementation defined name of a type in runtime by using the .name() member function of the std::type_info object returned by typeid. #include <iostream> #include <typeinfo> int main() { int speed = 110; std::cout << typeid(speed).name() <...

Here is an example of basic overriding in Python (for the sake of clarity and compatibility with both Python 2 and 3, using new style class and print with ()): class Parent(object): def introduce(self): print("Hello!") def print_name(self): print("Parent...

4.0 Instead of the ForEach-Object cmdlet, the here is also the possibility to use a ForEach method directly on object arrays like so (1..10).ForEach({$_ * $_}) or - if desired - the parentheses around the script block can be omitted (1..10).ForEach{$_ * $_} Both will result in the output ...

PrimitiveBoxed TypeMemory Size of primitive / boxedbooleanBoolean1 byte / 16 bytesbyteByte1 byte / 16 bytesshortShort2 bytes / 16 bytescharChar2 bytes / 16 bytesintInteger4 bytes / 16 byteslongLong8 bytes / 16 bytesfloatFloat4 bytes / 16 bytesdoubleDouble8 bytes / 16 bytes Boxed objects always requ...

UPDATE person SET state = 'NY' WHERE city = 'New York';

Everything in .NET is an object, hence every type has ToString() method defined in Object class which can be overridden. Default implementation of this method just returns the name of the type: public class Foo { } var foo = new Foo(); Console.WriteLine(foo); // outputs Foo ToString() is i...

The Comparable<T> interface requires one method: public interface Comparable<T> { public int compareTo(T other); } And the Comparator<T> interface requires one method: public interface Comparator<T> { public int compare(T t1, T t2); } These two met...

Variables declared inside a function only exist (unless passed) inside that function. x <- 1 foo <- function(x) { y <- 3 z <- x + y return(z) } y Error: object 'y' not found Variables passed into a function and then reassigned are overwritten, but only insi...

Variables can be assigned globally from any environment using <<-. bar() can now access y. bar <- function() { z <- x + y return(z) } foo <- function() { y <<- 3 z <- bar() return(z) } foo() 4 Global assignment is highly discourag...

Environments in R can be explicitly call and named. Variables can be explicitly assigned and call to or from those environments. A commonly created environment is one which encloses package:base or a subenvironment within package:base. e1 <- new.env(parent = baseenv()) e2 <- new.env(parent ...

Programming in general often requires a decision or a branch within the code to account for how the code operates under different inputs or conditions. Within the C# programming language (and most programming languages for this matter), the simplest and sometimes the most useful way of creating a br...

Following on from the If-Else Statement example, it is now time to introduce the Else If statement. The Else If statement follows directly after the If statement in the If-Else If-Else structure, but intrinsically has has a similar syntax as the If statement. It is used to add more branches to the c...

The option -v followed by an assignment of the form variable=value can be used to pass parameters to an awk program. This is illustrated by the punishment program below, whose job is to write count times the sentence “I shall not talk in class.” on standard output. The following example uses the v...

// Checks a string to see if it is a palindrome bool function IsPalindrome(string input) { if (input.size() <= 1) { return true; } else if (input[0] == input[input.size() - 1]) { return IsPalindrome(input.substr(1,input.size() - 2)); } else { r...

Custom events usually need custom event arguments containing information about the event. For example MouseEventArgs which is used by mouse events like MouseDown or MouseUp events, contains information about Location or Buttons which used to generate the event. When creating new events, to create a...