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Downcasting in Java
... String
When a cast (such as this last one) fails at runtime a ClassCastException will be thrown.
In other cases it will work:
Object o = "a String";
String s = (String) o; // this will work, since o references a String
Note that some casts will be disallowed at compile time, because they will...
Multiline strings in VB.NET
...
You can use XML Literals to achieve a similar effect:
Imports System.XML
Imports System.XML.Linq
Imports System.Core
Dim s As String = <a>Hello
World</a>.Value
Remember that if you have special characters, you should use a ...
Java Try Catch Finally blocks without Catch
...The program has a try and a finally block only. Since the catch block is excluded, how does the try block work if it encounters an exception or anything throwable? Does it just go directly to the finally block?
...
Using openssl to get the certificate from a server
...o get the right certificate.
openssl s_client -showcerts -servername www.example.com -connect www.example.com:443 </dev/null
Without SNI
If the remote server is not using SNI, then you can skip -servername parameter:
openssl s_client -showcerts -connect www.example.com:443 </dev/null
...
python list by value not by reference [duplicate]
Let's take an example
11 Answers
11
...
quick random row selection in Postgres
...
You might want to experiment with OFFSET, as in
SELECT myid FROM mytable OFFSET floor(random()*N) LIMIT 1;
The N is the number of rows in mytable. You may need to first do a SELECT COUNT(*) to figure out the value of N.
Update (by Antony Hat...
Difference between map and collect in Ruby?
...ut no difference between map and collect).
Why do both map and collect exist in Ruby? The map function has many naming conventions in different languages. Wikipedia provides an overview:
The map function originated in functional programming languages but is today supported (or may be defined)...
How to save a plot as image on the disk?
... pdf() or similar
Plot your model
Close the device using dev.off()
Some example code for saving the plot to a png file:
fit <- lm(some ~ model)
png(filename="your/file/location/name.png")
plot(fit)
dev.off()
This is described in the (combined) help page for the graphical formats ?png, ?bmp,...
Switch statement fallthrough in C#?
...ersonal major reasons for loving switch vs. if/else if constructs. An example is in order here:
13 Answers
...
Create an empty object in JavaScript with {} or new Object()?
...le.
For defining empty objects they're technically the same. The {} syntax is shorter, neater (less Java-ish), and allows you to instantly populate the object inline - like so:
var myObject = {
title: 'Frog',
url: '/img/picture.jpg',
width: 300,
height: 200
...