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Helper functions are used in conjunction with select to identify variables to return. Unless otherwise noted, these functions expect a string as the first parameter match. Passing a vector or another object will generate an error. library(dplyr) library(nycflights13) starts_with starts_with al...

One needs the predicted probabilities in order to calculate the ROC-AUC (area under the curve) score. The cross_val_predict uses the predict methods of classifiers. In order to be able to get the ROC-AUC score, one can simply subclass the classifier, overriding the predict method, so that it would a...

You must to add to web.xml a configuration tag like this: <context-param> <param-name>facelets.SKIP_COMMENTS</param-name> <param-value>true</param-value> </context-param> Now you can use normal HTML comments tag <!-- and --> <!-- <...

the most common use case is to set pointer-events to none to prevent certain shapes or all of your drawing to capture mouse events, and to let the shapes underneath them to receive the events. If you hover over the area where the red circle overlaps the blue circle, the blue circle will still rece...

A constant expression is an expression that yields a primitive type or a String, and whose value can be evaluated at compile time to a literal. The expression must evaluate without throwing an exception, and it must be composed of only the following: Primitive and String literals. Type ca...

In Apache Spark while doing shuffle operations like join and cogroup a lot of data gets transferred across network. Now, to control the number of partitions over which shuffle happens can be controlled by configurations given in Spark SQL. That configuration is as follows: spark.sql.shuffle.partiti...

Java expressions are evaluated following the following rules: Operands are evaluated from left to right. The operands of an operator are evaluated before the operator. Operators are evaluated according to operator precedence Argument lists are evaluated from left to right. Simple Example I...

Objects become eligible for garbage collection (GC) if they are no longer reachable by the main entry point(s) in a program. GC is usually not performed explicitly by the user, but to let the GC know an object is no longer needed a developer can: Dereference / assign null someFunction { var ...

1- Define Your own custom Block typedef void(^myCustomCompletion)(BOOL); 2- Create custom method which takes your custom completion block as a parameter. -(void) customMethodName:(myCustomCompletion) compblock{ //do stuff // check if completion block exist; if we do not check it will ...

React components that are pure functions of their props and do not require any internal state can be written as JavaScript functions instead of using the standard class syntax, as: import React from 'react' const HelloWorld = (props) => ( <h1>Hello, {props.name}!</h1> ); ...

To use typescript with react in a node project, you must first have a project directory initialized with npm. To initialize the directory with npm init Installing via npm or yarn You can install React using npm by doing the following: npm install --save react react-dom Facebook released its ow...

The simplest react component without a state and no properties can be written as: import * as React from 'react'; const Greeter = () => <span>Hello, World!</span> That component, however, can't access this.props since typescript can't tell if it is a react component. To access ...

Campaign Monitor built a nifty tool that generates code for buttons in HTML email. It uses a cominbation os CSS and VML (for Microsoft Outlook) to display background images or patterns in most major email clients. <div><!--[if mso]> <v:roundrect xmlns:v="urn:schemas-microsoft...

This technique relies on padding at the table cell level to structure the button, and both HTML attributes and CSS to style the button. No VML means simpler code, but no background images in Outlook. <table width="100%" border="0" cellspacing="0" cellpadding="0...

This technique relies on adding thick borders to the link itself to build the button's CTA. Using borders is universally understood by email clients, but limit button appearance solid colors. <table width="100%" border="0" cellspacing="0" cellpadding="0"&g...

This technique uses a combination of border-based and padding-based buttons, styling the link with both padding and at least a solid 1px border. The background color needs to be applied to the instead of the in this instance because Outlook does recognize horizontal padding on the tag (since it's...

This button derives from this example by Email on Acid. It is entirely code-based, so it will display without images downloaded, and the entire button is hoverable + clickable. Additionally, this example also includes spacers to help control how much vertical space appears before and after the butt...

SELECT 1 NUM_COLUMN, 'foo' VARCHAR2_COLUMN from DUAL UNION ALL SELECT NULL, NULL from DUAL; NUM_COLUMNVARCHAR2_COLUMN1foo(null)(null)

SELECT 3 * NULL + 5, 'Hello ' || NULL || 'world' from DUAL; 3*NULL+5'HELLO'||NULL||'WORLD'(null)Hello world

SELECT COALESCE(a, b, c, d, 5) FROM (SELECT NULL A, NULL b, NULL c, 4 d FROM DUAL); COALESCE(A,B,C,D,5)4 In some case, using COALESCE with two parameters can be faster than using NVL when the second parameter is not a constant. NVL will always evaluate both parameters. COALESCE will stop a...