Tutorial by Examples: l

// 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 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); ...

Note: Browsers are in the process of adding a built-in context.ellipse drawing command, but this command is not universally adopted (notably not in IE). The methods below work in all browsers. Draw an ellipse given it's desired top-left coordinate: // draws an ellipse based on x,y being top-left...

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!&...

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...

Create a Java class which extends org.apache.hadoop.hive.ql.exec.hive.UDAF Create an inner class which implements UDAFEvaluator Implement five methods init() – This method initializes the evaluator and resets its internal state. We are using new Column() in the code below to indicate th...

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...

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 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...

%storemagic stores variables and macros on IPython's database. To automatically restore stored variables at startup add this to ipython_config.py: c.StoreMagic.autorestore = True Example: In [1]: l = ['hello',10,'world'] In [2]: %store l In [3]: exit (IPython session is closed and started...

You may install Composer locally, as part of your project, or globally as a system wide executable. Locally To install, run these commands in your terminal. php -r "copy('https://getcomposer.org/installer', 'composer-setup.php');" # to check the validity of the downloaded installer, ch...

filePath = "file.csv" data = np.genfromtxt(filePath) Many options are supported, see official documentation for full list: data = np.genfromtxt(filePath, dtype='float', delimiter=';', skip_header=1, usecols=(0,1,3) )

I have some data analysis done on some data and have many 'non-coding' people on the team, who have similar data like mine, and have similar analysis requirements. In such cases, I can build a web application with shiny, which takes in user specific input data files, and generate analyses. I ...

A nested loop is a loop within a loop, an inner loop within the body of an outer one. How this works is that the first pass of the outer loop triggers the inner loop, which executes to completion. Then the second pass of the outer loop triggers the inner loop again. This repeats until the outer loop...

Searching git log using some string in log: git log [options] --grep "search_string" Example: git log --all --grep "removed file" Will search for removed file string in all logs in all branches. Starting from git 2.4+, the search can be inverted using the --invert-grep...

Reading invalid UTF-8 When reading UTF-8 encoded data, it is important to be aware of the fact the UTF-8 encoded data can be invalid or malformed. Such data should usually not be accepted by your program (unless you know what you are doing). When unexpectedly encountering malformed data, different ...

Objective C NSURL *url = [NSURL URLWithString:@"YOUR URL"]; AVPlayer *player = [AVPlayer playerWithURL:videoURL]; AVPlayerLayer *playerLayer = [AVPlayerLayer playerLayerWithPlayer:player]; playerLayer.frame = self.view.bounds; [self.view.layer addSublayer:playerLayer]; [player play];...