Tutorial by Examples: me

Delete ALL documents with a 'farewell' property set to 'okay'. const MongoClient = require('mongodb').MongoClient; const url = 'mongodb://localhost:27017/test'; MongoClient.connect(url, function (err, db) { if (err) throw new Error(err); db.collection('myCollection').deleteMany(// M...

.find() method allows us to search through the descendants of these elements in the DOM tree and construct a new jQuery object from the matching elements. HTML <div class="parent"> <div class="children" name="first"> <ul> ...

for arg; do echo arg=$arg done A for loop without a list of words parameter will iterate over the positional parameters instead. In other words, the above example is equivalent to this code: for arg in "$@"; do echo arg=$arg done In other words, if you catch yourself wri...

# The following shell function will be used to generate completions for # the "nuance_tune" command. _nuance_tune_opts () { local curr_arg prev_arg curr_arg=${COMP_WORDS[COMP_CWORD]} prev_arg=${COMP_WORDS[COMP_CWORD-1]} # The "config" option takes a file arg, so ...

We are so used to the name D3.js that it's possible to forget that D3 is actually DDD (Data-Driven Documents). And that's what D3 does well, a data-driven approach to DOM (Document Object Model) manipulation: D3 binds data to DOM elements and manipulates those elements based on the bounded data. Le...

Arrow functions do not expose an arguments object; therefore, arguments would simply refer to a variable in the current scope. const arguments = [true]; const foo = x => console.log(arguments[0]); foo(false); // -> true Due to this, arrow functions are also not aware of their caller/ca...

A JDK installation and a text editor are the bare minimum for Java development. (It is nice to have a text editor that can do Java syntax highlighting, but you can do without.) However for serious development work it is recommended that you also use the following: A Java IDE such as Eclipse, In...

The format statement applies the given format to the specified variable for display purposes only, i.e. the underlying value does not change. data example1 ; Date = '02AUG2016'd ; /* stored as a SAS date, i.e. a number */ Date2 = '31AUG2016'd ; format Date monyy7. Date2 yymmddn8. ; run...

Idiom specific adjustments can be done from C# code, for example for changing the layout orientation whether the view is shown or a phone or a tablet. if (Device.Idiom == TargetIdiom.Phone) { this.panel.Orientation = StackOrientation.Vertical; } else { this.panel.Orientation = Stac...

Adjustments can be done for specific platforms from C# code, for example for changing padding for all the targeted platforms. if (Device.OS == TargetPlatform.iOS) { panel.Padding = new Thickness (10); } else { panel.Padding = new Thickness (20); } An helper method is also availab...

The function in this example returns true if two line segments are intersecting and false if not. The example is designed for performance and uses closure to hold working variables // point object: {x:, y:} // p0 & p1 form one segment, p2 & p3 form the second segment // Retur...

// [x0,y0] to [x1,y1] define a line segment // [cx,cy] is circle centerpoint, cr is circle radius function isCircleSegmentColliding(x0,y0,x1,y1,cx,cy,cr){ // calc delta distance: source point to line start var dx=cx-x0; var dy=cy-y0; // calc delta distance: line start to e...

// var rect={x:,y:,width:,height:}; // var line={x1:,y1:,x2:,y2:}; // Get interseting point of line segment & rectangle (if any) function lineRectCollide(line,rect){ // p=line startpoint, p2=line endpoint var p={x:line.x1,y:line.y1}; var p2={x:line.x2,y:line.y2}; // to...

# Will display task as: # -------- Rebuild -------- # -------- Build -------- FormatTaskName "-------- {0} --------" # will display tasks in yellow colour: # Running Rebuild FormatTaskName { param($taskName) "Running $taskName" - foregroundcolor yellow } ...

The simplest way to understand creating and modifying SVG elements is to operate on the elements using the DOM Level 2 Core interfaces, as you would with HTML or XML. It is imperative that the elements created from JavaScript are created in the same namespace declared in the SVG element - in this e...

Using the mouse to drag an SVG element (or group of elements) can be accomplished by: Adding mousedown handler to starts the drag: adding a translation on the element to use during dragging (if needed), tracking mousemove events, and adding a mouseup handler to end the drag. During mousemove, tr...

# Set The Formatting $xmlsettings = New-Object System.Xml.XmlWriterSettings $xmlsettings.Indent = $true $xmlsettings.IndentChars = " " # Set the File Name Create The Document $XmlWriter = [System.XML.XmlWriter]::Create("C:\YourXML.xml", $xmlsettings) # Write the XML ...

Many languages feature a with statement that allows programmers to omit the receiver of method calls. with can be easily emulated in Ruby using instance_eval: def with(object, &block) object.instance_eval &block end The with method can be used to seamlessly execute methods on object...

If you can use memory-optimized tables, you can store JSON as text: CREATE TABLE ProductCollection ( Id int identity primary key nonclustered, Data nvarchar(max) ) WITH (MEMORY_OPTIMIZED=ON) Advantages of JSON in in-memory: JSON data is always in memory so there is no disk access Ther...

PL/SQL uses IN, OUT, IN OUT keywords to define what can happen to a passed parameter. IN specifies that the parameter is read only and the value cannot be changed by the procedure. OUT specifies the parameter is write only and a procedure can assign a value to it, but not reference the value. IN ...