Tutorial by Examples: r

The Error Log is populated with start and stop information, and critical events encountered by the server. The following is an example of its contents: The variable log_error holds the path to the log file for error logging. In the absence of a configuration file entry for log_error, the system...

Draw stars with flexible styling (size, colors, number-of-points). // Usage: drawStar(75,75,5,50,25,'mediumseagreen','gray',9); drawStar(150,200,8,50,25,'skyblue','gray',3); drawStar(225,75,16,50,20,'coral','transparent',0); drawStar(300,200,16,50,40,'gold','gray',3); // centerX, centerY: ...

// Usage: drawLineWithArrows(50,50,150,50,5,8,true,true); // x0,y0: the line's starting point // x1,y1: the line's ending point // width: the distance the arrowhead perpendicularly extends away from the line // height: the distance the arrowhead extends backward from the endpoint // arrow...

// Usage: var p0={x:50,y:100}; var p1={x:100,y:0}; var p2={x:200,y:200}; var p3={x:300,y:100}; cubicCurveArrowHeads(p0, p1, p2, p3, 15, true, true); quadraticCurveArrowHeads(p0, p1, p2, 15, true, true); // or use defaults true for both ends with arrow heads cubicCurveArrowHeads(p0, p...

// Usage: var arc={ cx:150, cy:150, innerRadius:75, outerRadius:100, startAngle:-Math.PI/4, endAngle:Math.PI } drawArc(arc,'skyblue','gray',4); function drawArc(a,fill,stroke,strokewidth){ ctx.beginPath(); ctx.arc(a.cx,a.cy,a.innerRadius,a.startAngle,a.endAngle); ...

When Canvas draws a line it automatically adds anti-aliasing to visually heal "jaggedness". The result is a line that is less jagged but more blurry. This function draws a line between 2 points without anti-aliasing using Bresenham's_line algorithm. The result is a crisp line without the ...

A regular polygon has all sides equal length. // Usage: drawRegularPolygon(3,25,75,50,6,'gray','red',0); drawRegularPolygon(5,25,150,50,6,'gray','gold',0); drawRegularPolygon(6,25,225,50,6,'gray','lightblue',0); drawRegularPolygon(10,25,300,50,6,'gray','lightgreen',0); function drawRegular...

<?xml version="1.0" encoding="utf-8"?> <s:Application xmlns:fx="http://ns.adobe.com/mxml/2009" xmlns:s="library://ns.adobe.com/flex/spark" xmlns:mx="library://ns.adobe.com/flex/mx"> <s:Label text="Hello World!&...

adb devices Is your phone displaying? If not, enable developer mode on your phone, and connect it by USB. adb reverse tcp:8081 tcp:8081 : In order to link correctly your phone and that React-Native recognize him during build. (NOTE:Android Version 5 or above.) react-native run-andr...

Before you start the cherry-pick process, you can check if the commit you want to cherry-pick already exists in the target branch, in which case you don't have to do anything. git branch --contains <commit> lists local branches that contain the specified commit. git branch -r --contains <...

Bounded type parameters allow you to set restrictions on generic type arguments: class SomeClass { } class Demo<T extends SomeClass> { } But a type parameter can only bind to a single class type. An interface type can be bound to a type that already had a binding. This is achieve...

When attempting to print something for debugging in vimscript, it is tempting to simply do the following. echo "Hello World!" However, in the context of a complex plugin, there are often many other things happening right after you attempt to print your message, so it is important to ad...

A regex pattern where a DOTALL modifier (in most regex flavors expressed with s) changes the behavior of . enabling it to match a newline (LF) symbol: /cat (.*?) dog/s This Perl-style regex will match a string like "cat fled from\na dog" capturing "fled from\na" into Group 1....

Another example is a MULTILINE modifier (usually expressed with m flag (not in Oniguruma (e.g. Ruby) that uses m to denote a DOTALL modifier)) that makes ^ and $ anchors match the start/end of a line, not the start/end of the whole string. /^My Line \d+$/gm will find all lines that start with My...

The common modifier to ignore case is i: /fog/i will match Fog, foG, etc. The inline version of the modifier looks like (?i). Notes: In Java, by default, case-insensitive matching assumes that only characters in the US-ASCII charset are being matched. Unicode-aware case-insensitive matching c...

The modifier that allows using whitespace inside some parts of the pattern to format it for better readability and to allow comments starting with #: /(?x)^ # start of string (?=\D*\d) # the string should contain at least 1 digit (?!\d+$) # the string cannot consist of digi...

This is a .NET regex specific modifier expressed with n. When used, unnamed groups (like (\d+)) are not captured. Only valid captures are explicitly named groups (e.g. (?<name> subexpression)). (?n)(\d+)-(\w+)-(?<id>\w+) will match the whole 123-1_abc-00098, but (\d+) and (\w+) won't...

The UNICODE modifier, usually expressed as u (PHP, Python) or U (Java), makes the regex engine treat the pattern and the input string as Unicode strings and patterns, make the pattern shorthand classes like \w, \d, \s, etc. Unicode-aware. /\A\p{L}+\z/u is a PHP regex to match strings that consis...

The PCRE-compliant PCRE_DOLLAR_ENDONLY modifier that makes the $ anchor match at the very end of the string (excluding the position before the final newline in the string). /^\d+$/D is equal to /^\d+\z/ and matches a whole string that consists of 1 or more digits and will not match "123...

Another PCRE-compliant modifier expressed with /A modifier. If this modifier is set, the pattern is forced to be "anchored", that is, it is constrained to match only at the start of the string which is being searched (the "subject string"). This effect can also be achieved by ap...