Tutorial by Examples: g

Using the default constructor T variable = Activator.CreateInstance(typeof(T)); Using parameterized constructor T variable = Activator.CreateInstance(typeof(T), arg1, arg2);

Occasionally you'd want to catch an exception and throw it from a different thread or method while preserving the original exception stack. This can be done with ExceptionDispatchInfo: using System.Runtime.ExceptionServices; void Main() { ExceptionDispatchInfo capturedException = null; ...

Whenever a Python script is invoked from the command line, the user may supply additional command line arguments which will be passed on to the script. These arguments will be available to the programmer from the system variable sys.argv ("argv" is a traditional name used in most programmi...

The @Html.AntiForgeryToken() helper method protects against cross-site request forgery (or CSRF) attacks. It can be used by simply using the Html.AntiForgeryToken() helper within one of your existing forms and decorating its corresponding Controller Action with the [ValidateAntiForgeryToken] attri...

If you are able to download an update of Android Studio, but after it restarts nothing happens, check out the following example: After the patch was downloaded and Android Studio closed, open the terminal Go to your android studio folder, e.g. cd ~/android-studio Go to bin subfolder: cd bin ...

val emailRegex: Regex = "(.+)@(.+)\\.(.+)".r "[email protected]" match { case emailRegex(userName, domain, topDomain) => println(s"Hi $userName from $domain") case _ => println(s"This is not a valid email.") } In this example, the regex attem...

Messages printed from NSLog are displayed on Console.app even in the release build of your app, which doesn't make sense for printouts that are only useful for debugging. To fix this, you can use this macro for debug logging instead of NSLog. #ifdef DEBUG #define DLog(...) NSLog(__VA_ARGS__) #els...

To use Leaflet, load its stylesheet and JavaScript file to your page: <link rel="stylesheet" href="/css/leaflet.css" /> <script src="/js/leaflet.js"></script> These resources can be downloaded from a variety of locations such as Leaflet's homepage...

First, import the libraries that work with files: from os import listdir from os.path import isfile, join, exists A helper function to read only files from a directory: def get_files(path): for file in listdir(path): full_path = join(path, file) if isfile(full_path): ...

Java ThreadLocal is used to create thread local variables. It is known that threads of an Object share it’s variables, so the variable is not thread safe. We can use synchronization for thread safety but if we want to avoid synchronization,ThreadLocal allows us to create variables which are local to...

where clause By adding a where clause you can restrict the iterations to ones that satisfy the given condition. for i in 0..<5 where i % 2 == 0 { print(i) } // 0 // 2 // 4 let names = ["James", "Emily", "Miles"] for name in names where name.c...

If you need to call an Objective-C method from C code, you have two ways: using objc_msgSend, or obtaining the IMP (method implementation function pointer) and calling that. #import <objc/objc.h> @implementation Example - (double)negate:(double)value { return -value; } - (doubl...

// *** Find movies except given ids *** NSPredicate *filterByNotInIds = [NSPredicate predicateWithFormat:@"NOT (self.id IN %@)",@[@"7CDF6D22-8D36-49C2-84FE-E31EECCECB79", @"7CDF6D22-8D36-49C2-84FE-E31EECCECB76"]]; NSLog(@"Filter movies except given Ids : %@"...

// *** Case Insensitive comparison with matching subset *** NSPredicate *filterByName = [NSPredicate predicateWithFormat:@"self.title CONTAINS[cd] %@",@"Tom"]; NSLog(@"Filter By Containing Name : %@",[array filteredArrayUsingPredicate:filterByName]);

There are times in which it is desirable to consolidate factor levels into fewer groups, perhaps because of sparse data in one of the categories. It may also occur when you have varying spellings or capitalization of the category names. Consider as an example the factor set.seed(1) colorful <...

To iterate over several generators in parallel, use the zip builtin: for x, y in zip(a,b): print(x,y) Results in: 1 x 2 y 3 z In python 2 you should use itertools.izip instead. Here we can also see that the all the zip functions yield tuples. Note that zip will stop iterating as soon...

C++17 C++17 introduces std::string_view, which is simply a non-owning range of const chars, implementable as either a pair of pointers or a pointer and a length. It is a superior parameter type for functions that requires non-modifiable string data. Before C++17, there were three options for this: ...

NSString *pathToPlist = [[NSBundle mainBundle] pathForResource:@"plistName" ofType:@"plist"]; NSDictionary *plistDict = [[NSDictionary alloc] initWithContentsOfFile:pathToPlist];

It is usually not a good idea to mix signed and unsigned integers in arithmetic operations. For example, what will be output of following example? #include <stdio.h> int main(void) { unsigned int a = 1000; signed int b = -1; if (a > b) puts("a is more than b&quot...

public bool IsTypeNullable<T>() { return Nullable.GetUnderlyingType( typeof(T) )!=null; }