Tutorial by Examples: re

The break keyword can be used in switch statements to exit the statement before evaluating all conditions. Example: switch('Condition') { 'Condition' { 'First Action' } 'Condition' { 'Second Action' break } 'Condition' { 'Third Action' } } Output...
Compile errors can be generated using the preprocessor. This is useful for a number of reasons some of which include, notifying a user if they are on an unsupported platform or an unsupported compiler. e.g. Return Error if gcc version is 3.0.0 or earlier. #if __GNUC__ < 3 #error "This cod...
% Define serial port with a baud rate of 115200 rate = 115200; if ispc s = serial('COM1', 'BaudRate',rate); elseif ismac % Note that on OSX the serial device is uniquely enumerated. You will % have to look at /dev/tty.* to discover the exact signature of your % serial device ...
Assuming you created the serial port object s as in this example, then % Read one byte data = fread(s, 1); % Read all the bytes, version 1 data = fread(s); % Read all the bytes, version 2 data = fread(s, s.BytesAvailable); % Close the serial port fclose(s);
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...
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) ...
To retrieve the result of a procedure call (e.g. Function or Property Get procedures), put the call on the right-hand side of an assignment: result = ProcedureName result = ProcedureName(argument1, argument2) Parentheses must be present if there are parameters. If the procedure has no parameter...
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. ...
NSArray *array1 = [NSArray arrayWithObjects:@"one", @"two", @"three", nil]; NSArray *array2 = @[@"one", @"two", @"three"];
Procedures do something. Name them after what they're doing, using a verb. If accurately naming a procedure is not possible, likely the procedure is doing too many things and needs to be broken down into smaller, more specialized procedures. Some common VBA naming conventions go thus: For all Pr...
Similar to the while loop, only the control statement is evaluated after the loop. Therefore, the loop will always execute at least once. var i: Int = 0 repeat { print(i) i += 1 } while i < 3 // 0 // 1 // 2
When you need to remove a specific value from an array, you can use the following one-liner to create a copy array without the given value: array.filter(function(val) { return val !== to_remove; }); Or if you want to change the array itself without creating a copy (for example if you write a fun...
From NSString: NSString *urlString = @"https://www.stackoverflow.com"; NSURL *myUrl = [NSURL URLWithString: urlString]; You can also use the following methods: - initWithString: + URLWithString:relativeToURL: - initWithString:relativeToURL: + fileURLWithPath:isDirectory: - initF...
To select the children of an element you can use the children() method. <div class="parent"> <h2>A headline</h2> <p>Lorem ipsum dolor sit amet...</p> <p>Praesent quis dolor turpis...</p> </div> Change the color of all the ...
// View to hold the CAGradientLayer. let view: UIView = UIView(frame: CGRect(x: 0, y: 0, width: 320, height: 320)) // Initialize gradient layer. let gradientLayer: CAGradientLayer = CAGradientLayer() // Set frame of gradient layer. gradientLayer.frame = view.bounds // Color at...
By default the Python random module use the Mersenne Twister PRNG to generate random numbers, which, although suitable in domains like simulations, fails to meet security requirements in more demanding environments. In order to create a cryptographically secure pseudorandom number, one can use Syst...
docker restart <container> [<container>...] Option --time : Seconds to wait for stop before killing the container (default 10) docker restart <container> --time 10
This thread-safe version of a singleton was necessary in the early versions of .NET where static initialization was not guaranteed to be thread-safe. In more modern versions of the framework a statically initialized singleton is usually preferred because it is very easy to make implementation mistak...
The flow of execution of a Ruby block may be controlled with the break, next, and redo statements. break The break statement will exit the block immediately. Any remaining instructions in the block will be skipped, and the iteration will end: actions = %w(run jump swim exit macarena) index = 0 ...

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