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db.posts.find().forEach(function(doc){ if(!doc.foo){ db.posts.update({_id: doc._id}, {$set:{'foo':''}}, false, true); } });

Purpose Use the CREATE SEQUENCE statement to create a sequence, which is a database object from which multiple users may generate unique integers. You can use sequences to automatically generate primary key values. When a sequence number is generated, the sequence is incremented, independent of th...

Backbone.js is made up of four separate components: Collections, Models, Routers, and Views. Each of these serve different purposes: Model - represents a single data object, but adds additional functionalities not provided by native JavaScript objects, such as an event system and a more conveni...

XML fragments, also known under the name of external parsed entities, can be stored in separate files. XML fragments, unlike XML documents, are less restrictive, in that several elements can appear top-level, as well as text nodes. Like an XML document, an external parsed entity may begin with an X...

AndroidManifest.xml: <activity android:name="com.example.MainActivity" > <intent-filter> <action android:name="android.intent.action.VIEW" /> <category android:name="android.intent.category.DEFAULT" /> <categ...

<script src="example.js"></script> The src attribute works like the href attribute on anchors: you can either specify an absolute or relative URL. The example above links to a file inside the same directory of the HTML document. This is typically added inside the <head&gt...

The classpath is a sequence of entries which are directory pathnames, JAR or ZIP file pathnames, or JAR / ZIP wildcard specifications. For a classpath specified on the command line (e.g. -classpath) or as an environment variable, the entries must be separated with ; (semicolon) characters on Wi...

Create a new project It can be just a Single View Application. Add the code Create a new Cocoa Touch Class file (File > New > File... > iOS > Cocoa Touch Class). Name it MyCollectionViewCell. This class will hold the outlets for the views that you add to your cell in the storyboard. ...

An extension to PHP called Xdebug is available to assist in profiling PHP applications, as well as runtime debugging. When running the profiler, the output is written to a file in a binary format called "cachegrind". Applications are available on each platform to analyze these files. To...

NSMutableAttributedString *attributeString = [[NSMutableAttributedString alloc] initWithString:@"Your String here"]; [attributeString addAttribute:NSStrikethroughStyleAttributeName value:@2 range:NSMakeRange(0, [attributeString length])];

Gray Level Co-Occurrence Matrix (Haralick et al. 1973) texture is a powerful image feature for image analysis. The glcm package provides a easy-to-use function to calculate such texutral features for RasterLayer objects in R. library(glcm) library(raster) r <- raster("C:/Program Files/R...

import scala.util.parsing.combinator._ class SimpleParser extends RegexParsers { // Define a grammar rule, turn it into a regex, and apply it the input. def word: Parser[String] = """[A-Z][a-z]+""".r ^^ { _.toString } } object SimpleParser extends SimplePar...

Sometimes you need to call a Tcl command from your expression. For example, supposing you need the length of a string in it. To do that, you just use a [...] sequence in the expression: set halfTheStringLength [expr { [string length $theString] / 2 }] You can call any Tcl command this way, but i...

$ git show HEAD^{/fix nasty bug} # find starting from HEAD $ git show ':/fix nasty bug' # find starting from any branch A colon (':'), followed by a slash ('/'), followed by a text, names a commit whose commit message matches the specified regular expression. This name returns the younge...

This example shows how a label's width can automatically resize when the text content changes. Pin the left and top edges Just use auto layout to add constraints to pin the left and top sides of the label. After that it will automatically resize. Notes This example comes from this Stack...

Suppose the following generic interface has been declared: public interface MyGenericInterface<T> { public void foo(T t); } Below are listed the possible ways to implement it. Non-generic class implementation with a specific type Choose a specific type to replace the formal type ...

This option enables the use of call profiling for code optimizations. Profiling records useful runtime statistics specific to the application and can—in many cases—increase performance because JVM can then act on those statistics. Note: This option is supported with the JRockit JVM R27.3.0 and la...

This option disables the fat lock spin code in Java, allowing threads that block trying to acquire a fat lock go to sleep directly. Objects in Java become a lock as soon as any thread enters a synchronized block on that object. All locks are held (that is, stayed locked) until released by the locki...

This option disables the garbage collector strategy changes. Compaction heuristics and nursery size heuristics are not affected by this option. By default, the garbage collection heuristics are enabled. Usage: -XXdisableFatSpin

This option causes a dump file to be generated and allows you to specify the relative size of that file (that is, small, medium, or large). Usage: -XXdumpsize:<size> <size>DescriptionnoneDoes not generate a dump file.smallOn Windows, a small dump file is generated (on Linux a full c...