Subscription returns an IDisposable:
IDisposable subscription = emails.Subscribe(email =>
Console.WriteLine("Email from {0} to {1}", email.From, email.To));
When you are ready to unsubscribe, simply dispose the subscription:
subscription.Dispose();
The following is a bad idea because it would dispose the db variable before returning it.
public IDBContext GetDBContext()
{
using (var db = new DBContext())
{
return db;
}
}
This can also create more subtle mistakes:
public IEnumerable<Person> GetPeople(int age)...
R has several built-in functions that can be used to print or display information, but print and cat are the most basic. As R is an interpreted language, you can try these out directly in the R console:
print("Hello World")
#[1] "Hello World"
cat("Hello World\n")
#H...
If it's not already done in php.ini, error reporting can be set dynamically and should be set to allow most errors to be shown:
Syntax
int error_reporting ([ int $level ] )
Examples
// should always be used prior to 5.4
error_reporting(E_ALL);
// -1 will show every possible error, even whe...
Dropbox.authorizedClient!.files.listFolder(path: "").response { response, error in
print("*** List folder ***")
if let result = response {
print("Folder contents:")
for entry in result.entries {
print(entry.name)
if ...
For Alerts since iOS 8, you would use a UIAlertController but for versions before, you would have used a UIAlertView, which is now deprecated.
8.0
var alert = UIAlertController.Create(title, message, UIAlertControllerStyle.Alert);
alert.AddAction(UIAlertAction.Create(otherTitle, UIAlertActionStyl...
We can make an AJAX request to Stack Exchange's API to retrieve a list of the top JavaScript questions for the month, then present them as a list of links. If the request fails or the returns an API error, our promise error handling displays the error instead.
6
View live results on HyperWeb.
c...
Use the --number flag to print line numbers before each line. Alternatively, -n does the same thing.
$ cat --number file
1 line 1
2 line 2
3
4 line 4
5 line 5
To skip empty lines when counting lines, use the --number-nonblank, or simply -b.
$ cat -b file
1 line 1
2 line ...
$( "#accordion" ).accordion( "disable" );
This method will disable the accordion, i.e. the headers are not selectable making the content read only and static.
This method does not take any arguments.
While inside a Razor code block, the browser will only recognize HTML code if the code is escaped.
Use @: for a Single line:
@foreach(int number in Model.Numbers)
{
@:<h1>Hello, I am a header!</h1>
}
Use <text> ... </text> for Multi-line:
@{
var number = 1;
...
This is a continuous collector that uses the hadoop fs -du -s /hbase/* command to get details about the HDFS disk usage. This metric is very useful for tracking space in an OpenTSDB system.
#!/bin/bash
while true; do
while read -r bytes raw_bytes path; do
echo "hdfs.du $(date +&...
The static (compile-time) type is used rather than the dynamic (run-time type) to match parameters.
public class Base
{
public virtual string GetName()
{
return "Base";
}
}
public class Derived : Base
{
public override string GetName()
{
...
Just execute lsb_release -a.
On Debian:
$ lsb_release -a
No LSB modules are available.
Distributor ID: Debian
Description: Debian GNU/Linux testing (stretch)
Release: testing
Codename: stretch
On Ubuntu:
$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubun...
By default error message appears below textbox in <div class="help-block"></div> on keyUp or after pressing submit button if any validation constraints aren't met.
Sometimes we want a message on submit only i.e. no validation at onKeyup event.
Let's check yii2/widgets/ActiveF...
A button can be disabled by
Swift
myButton.isEnabled = false
Objective-C:
myButton.enabled = NO;
The button will become gray:
If you don't want the button appearance to change when disabled set adjustsImageWhenDisabled to false / NO
When defining discriminated unions you can name elements of tuple types and use these names during pattern matching.
type Shape =
| Circle of diameter:int
| Rectangle of width:int * height:int
let shapeIsTenWide = function
| Circle(diameter=10)
| Rectangle(width=10) -> t...
Returns unique values from an IEnumerable. Uniqueness is determined using the default equality comparer.
int[] array = { 1, 2, 3, 4, 2, 5, 3, 1, 2 };
var distinct = array.Distinct();
// distinct = { 1, 2, 3, 4, 5 }
To compare a custom data type, we need to implement the IEquatable<T> i...
Discriminated unions in F# offer a a way to define types which may hold any number of different data types. Their functionality is similar to C++ unions or VB variants, but with the additional benefit of being type safe.
// define a discriminated union that can hold either a float or a string
type...
The following code is for iOS 8 and lower for creating a login alert.
// Create the UIAlertView
var loginAlertView = new UIAlertView(title, message, null, cancelTitle, okTitle);
// Setting the AlertViewStyle to UIAlertViewStyle.LoginAndPasswordInput
loginAlertView.AlertViewStyle = UIAlertViewS...