Tutorial by Examples: pt

To convert exceptions into Either or Option types, you can use methods that provided in scala.util.control.Exception import scala.util.control.Exception._ val plain = "71a" val optionInt: Option[Int] = catching(classOf[java.lang.NumberFormatException]) opt { plain.toInt } val eitherI...

You can override the default vmoptions with your own personal settings by choosing Help > Edit Custom VM Options from the Android Studio toolbar. This will create a local copy which you are free to edit. Alternatively, you can edit the default vmoptions directly using the paths given below. Note...

Prompt will display a dialog to the user requesting their input. You can provide a message that will be placed above the text field. The return value is a string representing the input provided by the user. var name = prompt("What's your name?"); console.log("Hello, " + name); ...

// Get the battery API navigator.getBattery().then(function(battery) { console.log( "Battery will drain in ", battery.dischargingTime, " seconds" ); });

In Java (and other languages), using null is a common way of indicating that there is no value attached to a reference variable. In Scala, using Option is preferred over using null. Option wraps values that might be null. None is a subclass of Option wrapping a null reference. Some is a subclass of...

ANTLR contains a testing tool in its runtime library, this tool can be used to display information detailing how the parsing is performed to match input against defined rules in your grammar file. To use this tool contained within the ANTLR jar file you should setup your systems classpath to allow ...

Use this binding to build options for a select item <select data-bind="options: gasGiants"></select> <script type="text/javascript"> var viewModel = { gasGiants: ko.observableArray(['Jupiter', 'Saturn', 'Neptune', 'Uranus']) }; </scri...

This example connects to a Wi-Fi access point with WEP encryption, given an SSID and the password. public boolean ConnectToNetworkWEP(String networkSSID, String password) { try { WifiConfiguration conf = new WifiConfiguration(); conf.SSID = "\"" + networkSSID ...

This example connects to a Wi-Fi access point with WPA2 encryption. public boolean ConnectToNetworkWPA(String networkSSID, String password) { try { WifiConfiguration conf = new WifiConfiguration(); conf.SSID = "\"" + networkSSID + "\""; // Please note th...

The command prompt comes pre-installed on all Windows NT, Windows CE, OS/2 and eComStation operating systems, and exists as cmd.exe, typically located in C:\Windows\system32\cmd.exe On Windows 7 the fastest ways to open the command prompt are: Press Win 𐌎, type "cmd" and then press ...

It's also possible to use data binding within your RecyclerView Adapter. Data model public class Item { private String name; public String getName() { return name; } } XML Layout <TextView android:layout_width="wrap_content" android:layou...

function transform(fn, arr) { let result = []; for (let el of arr) { result.push(fn(el)); // We push the result of the transformed item to result } return result; } console.log(transform(x => x * 2, [1,2,3,4])); // [2, 4, 6, 8] As you can see, our transform fun...

class CustomException implements Exception { String cause; CustomException(this.cause); } void main() { try { throwException(); } on CustomException { print("custom exception is been obtained"); } } throwException() { throw new CustomException('This is m...

To change PS1, you just have to change the value of PS1 shell variable. The value can be set in ~/.bashrc or /etc/bashrc file, depending on the distro. PS1 can be changed to any plain text like: PS1="hello " Besides the plain text, a number of backslash-escaped special characters are s...

First, create a key file, e.g., vault_pass_file, which ideally contains a long sequence of random characters. In linux systems you could use pwgen to create a random password file: pwgen 256 1 > vault_pass_file Then, use this file to encrypt sensitive data, e.g., groups_vars/group.yml: ANSI...

With Vault you can also encrypt non-structured data, such as private key files and still be able to decrypt them in your play with the lookup module. --- - name: Copy private key to destination copy: dest=/home/user/.ssh/id_rsa mode=0600 content=lookup('pipe', 'ANSIBLE_VAULT_PA...

You can run a play which relies on vault-encrypted templates by using the local_action module. --- - name: Decrypt template local_action: "shell {{ view_encrypted_file_cmd }} {{ role_path }}/templates/template.enc > {{ role_path }}/templates/template" changed_when: False - ...

proc myproc {} { puts "hi" } myproc # => hi An empty argument list (the second argument after the procedure name, "myproc") means that the procedure will not accept arguments.

proc myproc {alpha beta} { ... set foo $alpha set beta $bar ;# note: possibly useless invocation } myproc 12 34 ;# alpha will be 12, beta will be 34 If the argument list consists of words, those will be the names of local variables in the procedure, and their initi...

### Definition proc myproc {alpha {beta {}} {gamma green}} { puts [list $alpha $beta $gamma] } ### Use myproc A # => A {} green myproc A B # => A B green myproc A B C # => A B C This procedure accepts one, two, or three arguments: those parameters whose names are the fi...