Tutorial by Examples: nd

Functions have two built-in methods that allow the programmer to supply arguments and the this variable differently: call and apply. This is useful, because functions that operate on one object (the object that they are a property of) can be repurposed to operate on another, compatible object. Addi...

int a = 6; // 0110b (0x06) int b = 10; // 1010b (0x0A) int c = a & b; // 0010b (0x02) std::cout << "a = " << a << ", b = " << b << ", c = " << c << std::endl; Output a = 6, b = 10, c = 2 Why A bit wise A...

Some API calls can succeed or fail in more than one way. The APIs commonly return additional information for both successful invocations as well as errors (e.g. CreateMutex). if ( CreateMutexW( NULL, TRUE, L"Global\\MyNamedMutex" ) == NULL ) { // Failure: get additional information. ...

The begin block is a control structure that groups together multiple statements. begin a = 7 b = 6 a * b end A begin block will return the value of the last statement in the block. The following example will return 3. begin 1 2 3 end The begin block is useful for conditi...

HTTP 404 Not Found means that the server couldn't find the path using the URI that the client requested. HTTP/1.1 404 Not Found Most often, the requested file was deleted, but sometimes it can be a document root misconfiguration or a lack of permissions (though missing permissions more frequentl...

ceil() The ceil() method rounds a number upwards to the nearest integer, and returns the result. Syntax: Math.ceil(n); Example: console.log(Math.ceil(0.60)); // 1 console.log(Math.ceil(0.40)); // 1 console.log(Math.ceil(5.1)); // 6 console.log(Math.ceil(-5.1)); // -5 console.log(Math....

1. Target a device by serial number Use the -s option followed by a device name to select on which device the adb command should run. The -s options should be first in line, before the command. adb -s <device> <command> Example: adb devices List of devices attached emulator-55...

HTML also provides the tables with the <thead>, <tbody>, <tfoot>, and <caption> elements. These additional elements are useful for adding semantic value to your tables and for providing a place for separate CSS styling. When printing out a table that doesn't fit onto one (pa...

Useful if your program is outputting web pages along the way. from http.server import HTTPServer, CGIHTTPRequestHandler import webbrowser import threading def start_server(path, port=8000): '''Start a simple webserver serving path on port''' os.chdir(path) httpd = HTTPServer((''...

Say you have implemented some logic to detect attempts to modify an object in the database while the client that submitted changes didn't have the latest modifications. If such case happens, you raise a custom exception ConfictError(detailed_message). Now you want to return an HTTP 409 (Confict) st...

Creating empty deque: dl = deque() # deque([]) creating empty deque Creating deque with some elements: dl = deque([1, 2, 3, 4]) # deque([1, 2, 3, 4]) Adding element to deque: dl.append(5) # deque([1, 2, 3, 4, 5]) Adding element left side of deque: dl.appendleft(0) # deque([0, 1, 2, ...

In many other languages, if you run the following (Java example) if("asgdsrf" == 0) { //do stuff } ... you'll get an error. You can't just go comparing strings to integers like that. In Python, this is a perfectly legal statement - it'll just resolve to False. A common gotcha ...

<div tabindex="2">Second</div> <div tabindex="1">First</div> Positive values will insert the element at the tabbing order position of its respective value. Elements without preference (i.e. tabindex="0" or native elements such as button and a...

The spacing should be even and uniform throughout. Improper indentation can cause an IndentationError or cause the program to do something unexpected. The following example raises an IndentationError: a = 7 if a > 5: print "foo" else: print "bar" print "done&qu...

To get the size of a communicator (e.g. MPI_COMM_WORLD) and the local process' rank inside it: int rank, size; int res; MPI_Comm communicator = MPI_COMM_WORLD; res = MPI_Comm_rank (communicator, &rank); if (res != MPI_SUCCESS) { fprintf (stderr, "MPI_Comm_rank failed\n"); ...

PREPARE prepares a statement for execution EXECUTE executes a prepared statement DEALLOCATE PREPARE releases a prepared statement SET @s = 'SELECT SQRT(POW(?,2) + POW(?,2)) AS hypotenuse'; PREPARE stmt2 FROM @s; SET @a = 6; SET @b = 8; EXECUTE stmt2 USING @a, @b; Result: +------------+ |...

The pickle module implements an algorithm for turning an arbitrary Python object into a series of bytes. This process is also called serializing the object. The byte stream representing the object can then be transmitted or stored, and later reconstructed to create a new object with the same charact...

#include <stdlib.h> #include <stdio.h> int main(void) { result = EXIT_SUCCESS; char file_name[] = "outbut.bin"; char str[] = "This is a binary file example"; FILE * fp = fopen(file_name, "wb"); if (fp == NULL) /* If an erro...

#include <stdio.h> #include <stdlib.h> int main (void) { int * pdata; size_t n; printf ("Enter the size of the array: "); fflush(stdout); /* Make sure the prompt gets printed to buffered stdout. */ if (1 != scanf("%zu", &n)) /* If zu is n...

Adding a Conditional attribute from System.Diagnostics namespace to a method is a clean way to control which methods are called in your builds and which are not. #define EXAMPLE_A using System.Diagnostics; class Program { static void Main() { ExampleA(); // This method will ...