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As there is currently no simple way of combining dictionaries in Swift, it can be useful to overload the + and += operators in order to add this functionality using generics. // Combines two dictionaries together. If both dictionaries contain // the same key, the value of the right hand side dicti...
The SQL 2008 standard defines the FETCH FIRST clause to limit the number of records returned. SELECT Id, ProductName, UnitPrice, Package FROM Product ORDER BY UnitPrice DESC FETCH FIRST 10 ROWS ONLY This standard is only supported in recent versions of some RDMSs. Vendor-specific non-stand...
When NSLog is asked to print empty string, it omits the log completely. NSString *name = @""; NSLog(@"%@", name); // Resolves to @"" The above code will print nothing. It is a good practice to prefix logs with labels: NSString *name = @""; NSLog(@&quo...
The for clause of a list comprehension can specify more than one variable: [x + y for x, y in [(1, 2), (3, 4), (5, 6)]] # Out: [3, 7, 11] [x + y for x, y in zip([1, 3, 5], [2, 4, 6])] # Out: [3, 7, 11] This is just like regular for loops: for x, y in [(1,2), (3,4), (5,6)]: print(x+y) ...
Pojo Model public class Model { private String firstName; private String lastName; private int age; /* Getters and setters not shown for brevity */ } Example: String to Object Model outputObject = objectMapper.readValue( "{\"firstName\":\"J...
Parentheses are used to enclose the arguments of function calls. Using them for procedure calls can cause unexpected problems. Because they can introduce bugs, both at run-time by passing a possibly unintended value to the procedure, and at compile-time by simply being invalid syntax. Run-time Re...
It's possible to attach an object to an existing object as if there was a new property. This is called association and allows one to extend existing objects. It can be used to provide storage when adding a property via a class extension or otherwise add additional information to an existing object. ...
The Objective-C runtime allows you to change the implementation of a method at runtime. This is called method swizzling and is often used to exchange the implementations of two methods. For example, if the methods foo and bar are exchanged, sending the message foo will now execute the implementation...
NSArray *array1 = [NSArray arrayWithObjects:@"one", @"two", @"three", nil]; NSArray *array2 = @[@"one", @"two", @"three"];
You can use the <img> or <object> elements to embed external SVG elements. Setting the height and width is optional but is highly recommended. Using the image element <img src="attention.svg" width="50" height="50"> Using <img> does not allo...
SVG can be written directly into a HTML document. Inline SVG can be styled and manipulated using CSS and JavaScript. <body> <svg class="attention" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" viewBox="0 0 1000 1000&qu...
You can add external SVG files using the background-image property, just as you would do with any other image. HTML: <div class="attention"></div> CSS: .attention { background-image: url(attention.svg); background-size: 100% 100%; width: 50px; height: ...
You can split a string into an array of parts, divided by a separator character. NSString * yourString = @"Stack,Exchange,Network"; NSArray * yourWords = [yourString componentsSeparatedByString:@","]; // Output: @[@"Stack", @"Exchange", @"Network&quot...
To search if a String contains a substring, do the following: NSString *myString = @"This is for checking substrings"; NSString *subString = @"checking"; BOOL doesContainSubstring = [myString containsString:subString]; // YES If targeting iOS 7 or OS X 10.9 (or earlier)...
Unlike classes, structures cannot inherit: class MyView: NSView { } // works struct MyInt: Int { } // error: inheritance from non-protocol type 'Int' Structures, however, can adopt protocols: struct Vector: Hashable { ... } // works
If a case class has exactly two values, its extractor can be used in infix notation. case class Pair(a: String, b: String) val p: Pair = Pair("hello", "world") val x Pair y = p //x: String = hello //y: String = world Any extractor that returns a 2-tuple can work this way....
The for-in loop allows you to iterate over any sequence. Iterating over a range You can iterate over both half-open and closed ranges: for i in 0..<3 { print(i) } for i in 0...2 { print(i) } // Both print: // 0 // 1 // 2 Iterating over an array or set let names = [&quo...
You can use the Enumerable class alongside Linq queries to convert for loops into Linq one liners. Select Example Opposed to doing this: var asciiCharacters = new List<char>(); for (var x = 0; x < 256; x++) { asciiCharacters.Add((char)x); } You can do this: var asciiCharacter...
Composer tracks which versions of packages you have installed in a file called composer.lock, which is intended to be committed to version control, so that when the project is cloned in the future, simply running composer install will download and install all the project's dependencies. Composer de...
A lot of the power of ReactJS is its ability to allow nesting of components. Take the following two components: var React = require('react'); var createReactClass = require('create-react-class'); var CommentList = reactCreateClass({ render: function() { return ( <div className...

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