Tutorial by Examples: le

Interactive interpreter variables

Note that these only work in the developer tools of certain browsers. $_ gives you the value of whatever expression was evaluated last. "foo" // "foo" $_ // "foo" $0 refers to the DOM element currently selected in the Inspector. So if &l...

JavaScript • Debugging

Reference-Style Images

In this type of image addition, one image can be used several times without duplicating its URL, making it a good choice when using one image multiple times in a document. Markdown Source Picture of Duck: ![Duck][1] Same picture of Duck: ![Same Duck][1] [1]: http://i.stack.imgur.com/uk...

Markdown • Images

Dynamic / variable property names

Sometimes the property name needs to be stored into a variable. In this example, we ask the user what word needs to be looked up, and then provide the result from an object I've named dictionary. var dictionary = { lettuce: 'a veggie', banana: 'a fruit', tomato: 'it depends on who yo...

JavaScript • Objects

Finding an Element in std::vector

The function std::find, defined in the <algorithm> header, can be used to find an element in a std::vector. std::find uses the operator== to compare elements for equality. It returns an iterator to the first element in the range that compares equal to the value. If the element in question is...

C++ • std::vector

Alert when network becomes unavailable

- (void)reachabilityChanged:(NSNotification *)note { Reachability* reachability = [note object]; NetworkStatus netStatus = [reachability currentReachabilityStatus]; if (netStatus == NotReachable) { NSLog(@"Network unavailable"); } }

iOS • Checking for Network Connectivity

Alert when connection becomes a WIFI or cellular network

- (void)reachabilityChanged:(NSNotification *)note { Reachability* reachability = [note object]; NetworkStatus netStatus = [reachability currentReachabilityStatus]; switch (netStatus) { case NotReachable: NSLog(@"Network unavailable"); br...

iOS • Checking for Network Connectivity

Convert elements to strings and concatenate them, separated by commas

// Java: String joined = things.stream() .map(Object::toString) .collect(Collectors.joining(", ")); // Kotlin: val joined = things.joinToString() // ", " is used as separator, by default

Kotlin • Java 8 Stream Equivalents

Names of male members

// Java: List<String> namesOfMaleMembersCollect = roster .stream() .filter(p -> p.getGender() == Person.Sex.MALE) .map(p -> p.getName()) .collect(Collectors.toList()); // Kotlin: val namesOfMaleMembers = roster.filter { it.gender == Person.Sex.MALE }.map { it.nam...

Kotlin • Java 8 Stream Equivalents

Different Kinds of Streams #7 - lazily iterate Doubles, map to Int, map to String, print each

// Java: Stream.of(1.0, 2.0, 3.0) .mapToInt(Double::intValue) .mapToObj(i -> "a" + i) .forEach(System.out::println); // a1 // a2 // a3 // Kotlin: sequenceOf(1.0, 2.0, 3.0).map(Double::toInt).map { "a$it" }.forEach(::println)

Kotlin • Java 8 Stream Equivalents

Collect example #5 - find people of legal age, output formatted string

// Java: String phrase = persons .stream() .filter(p -> p.age >= 18) .map(p -> p.name) .collect(Collectors.joining(" and ", "In Germany ", " are of legal age.")); System.out.println(phrase); // In Germany Max and Peter a...

Kotlin • Java 8 Stream Equivalents

Collect example #6 - group people by age, print age and names together

// Java: Map<Integer, String> map = persons .stream() .collect(Collectors.toMap( p -> p.age, p -> p.name, (name1, name2) -> name1 + ";" + name2)); System.out.println(map); // {18=Max, 23=Peter;Pamela, ...

Kotlin • Java 8 Stream Equivalents

Collect example #7a - Map names, join together with delimiter

// Java (verbose): Collector<Person, StringJoiner, String> personNameCollector = Collector.of( () -> new StringJoiner(" | "), // supplier (j, p) -> j.add(p.name.toUpperCase()), // accumulator (j1, j2) -> j1.merge(j2), // c...

Kotlin • Java 8 Stream Equivalents

Collect example #7b - Collect with SummarizingInt

// Java: IntSummaryStatistics ageSummary = persons.stream() .collect(Collectors.summarizingInt(p -> p.age)); System.out.println(ageSummary); // IntSummaryStatistics{count=4, sum=76, min=12, average=19.000000, max=23} // Kotlin: // something to hold the stats... da...

Kotlin • Java 8 Stream Equivalents

External CSS Stylesheet

<link rel="stylesheet" href="path/to.css" type="text/css"> The standard practice is to place CSS <link> tags inside the <head> tag at the top of your HTML. This way the CSS will be loaded first and will apply to your page as it is loading, rather th...

HTML • Linking Resources

Building an image from a Dockerfile

Once you have a Dockerfile, you can build an image from it using docker build. The basic form of this command is: docker build -t image-name path If your Dockerfile isn't named Dockerfile, you can use the -f flag to give the name of the Dockerfile to build. docker build -t image-name -f Dockerfi...

Docker • Building images

A simple Dockerfile

FROM node:5 The FROM directive specifies an image to start from. Any valid image reference may be used. WORKDIR /usr/src/app The WORKDIR directive sets the current working directory inside the container, equivalent to running cd inside the container. (Note: RUN cd will not change the current ...

Docker • Building images

Low Memory Alert and Template

Templates can be previewed and edited using the Rule Editor tab in Bosun. Use the Jump to links to select the alert you want to edit, then you can use the template button next to macro to switch between the alert an template sections of the configuration. If an alert has multiple instances you can u...

Bosun • Templates: Overview

Embedded Templates and CSS Styles

You can embed another template body into your template via {{template "mysharedtemplate" .}} to reuse shared components. Here is an example that creates a header template that can be reused at the top of all other template bodies. It also uses CSS to stylize the output so that it is easier...

Bosun • Templates: Overview

Graph using Alert Variable

Using .Graph will filter the results to only include those that match the tagset for the alert. For instance an alert for os.low.memory{host=ny-web01} would only include series with the host=ny-web01 tags. If multiple series match then only the first matching result will be used. template graph.tem...

Bosun • Templates: Graph and GraphAll

GraphAll using Alert Variable

Using .GraphAll will include all the results in the graph. template graph.template { subject = ... body = `{{template "header" .}} <strong>GraphAll</strong> <div>{{.GraphAll .Alert.Vars.graph}}</div> <strong>GraphAll With Y Axis...

Bosun • Templates: Graph and GraphAll

Page 21 of 339

Get monthly updates about new articles, cheatsheets, and tricks.