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To convert exceptions into Either or Option types, you can use methods that provided in scala.util.control.Exception import scala.util.control.Exception._ val plain = "71a" val optionInt: Option[Int] = catching(classOf[java.lang.NumberFormatException]) opt { plain.toInt } val eitherI...

A very interesting type of JOIN is the LATERAL JOIN (new in PostgreSQL 9.3+), which is also known as CROSS APPLY/OUTER APPLY in SQL-Server & Oracle. The basic idea is that a table-valued function (or inline subquery) gets applied for every row you join. This makes it possible to, for example...

One type of JOIN that is less known, is the FULL JOIN. (Note: FULL JOIN is not supported by MySQL as per 2016) A FULL OUTER JOIN returns all rows from the left table, and all rows from the right table. If there are rows in the left table that do not have matches in the right table, or if there a...

Recursive joins are often used to obtain parent-child data. In SQL, they are implemented with recursive common table expressions, for example: WITH RECURSIVE MyDescendants AS ( SELECT Name FROM People WHERE Name = 'John Doe' UNION ALL SELECT People.Name FROM Peopl...

You can override the default vmoptions with your own personal settings by choosing Help > Edit Custom VM Options from the Android Studio toolbar. This will create a local copy which you are free to edit. Alternatively, you can edit the default vmoptions directly using the paths given below. Note...

If your array or array-like object is numeric, that is, if all its elements are numbers, then you can use Math.min.apply or Math.max.apply by passing null as the first argument, and your array as the second. var myArray = [1, 2, 3, 4]; Math.min.apply(null, myArray); // 1 Math.max.apply(null, my...

To read default configuration properties: package com.example; public class ExampleApplication { private Properties getDefaults() throws IOException { Properties defaults = new Properties(); try (InputStream defaultsStream = ExampleApplication.class.getResou...

SOAP services can publish metadata that describes the methods that may be invoked by clients. Clients can use tools such as Visual Studio to automatically generate code (known as client proxies). The proxies hide the complexity of invoking a service. To invoke a service, one merely invokes a metho...

To find the largest or smallest element stored in a vector, you can use the methods std::max_element and std::min_element, respectively. These methods are defined in <algorithm> header. If several elements are equivalent to the greatest (smallest) element, the methods return the iterator to th...

You can create your own tag helpers by implementing ITagHelper or deriving from the convenience class TagHelper. The default convention is to target an html tag that matches the name of the helper without the optional TagHelper suffix. For example WidgetTagHelper will target a <widget> ta...

View components encapsulate reusable pieces of logic and views. They are defined by: A ViewComponent class containing the logic for fetching and preparing the data for the view and deciding which view to render. One or more views Since they contain logic, they are more flexible than partial v...

The default project template creates a partial view _LoginPartial.cshtml which contains a bit of logic for finding out whether the user is logged in or not and find out its user name. Since a view component might be a better fit (as there is logic involved and even 2 services injected) the followin...

The alert() method of the window object displays an alert box with a specified message and an OK or Cancel button. The text of that button depends on the browser and can't be modified. Syntax alert("Hello world!"); // Or, alternatively... window.alert("Hello world!"); Prod...

Prompt will display a dialog to the user requesting their input. You can provide a message that will be placed above the text field. The return value is a string representing the input provided by the user. var name = prompt("What's your name?"); console.log("Hello, " + name); ...

A hello world topic should consist of the most basic, complete, runnable, starter program available, that may be achieved by the widest amount of versions of the language, framework or system being documented. If necessary, the remarks should include basic instructions on how to prepare and execute ...

Rotate a polygon clockwise by 90 degrees around the origin: <svg xmlns="http://www.w3.org/2000/svg"> <polygon points="0,0 30,0 15,20" transform="rotate(90)" /> </svg> The result is equivalent to <svg xmlns="http://www.w3.org/2000/svg...

Transformations can be concatenated and are applied right to left Rotate a rectangle by 90 degrees and then move it down by 20 units and to the right by 20 units: <svg xmlns="http://www.w3.org/2000/svg"> <rect x="-10" y="-20" width="20" height=...

<svg width="400" height="400"> <defs> <pattern id="pattern1" width="0.2" height="0.2" patternUnits="objectBoundingBox"> <circle cx="10" cy="10" r="10" fill="#0000ff" /&...

Let’s try some basic expression in the REPL: CL-USER> (+ 1 2 3) 6 CL-USER> (- 3 1 1) 1 CL-USER> (- 3) -3 CL-USER> (+ 5.3 (- 3 2) (* 2 2)) 10.3 CL-USER> (concatenate 'string "Hello, " "World!") "Hello, World!" CL-USER> The basic building ...

Two popular options are to use: ipython notation: In [11]: df = pd.DataFrame([[1, 2], [3, 4]]) In [12]: df Out[12]: 0 1 0 1 2 1 3 4 Alternatively (this is popular over in the python documentation) and more concisely: df.columns # Out: RangeIndex(start=0, stop=2, step=1) df[0...