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What is the difference between Scala's case class and class?
...xclusively depend on their constructor arguments.
This functional concept allows us to
use a compact initialization syntax (Node(1, Leaf(2), None)))
decompose them using pattern matching
have equality comparisons implicitly defined
In combination with inheritance, case classes are used to mimi...
UITextField text change event
...
From proper way to do uitextfield text change call back:
I catch the characters sent to a UITextField control something like this:
// Add a "textFieldDidChange" notification method to the text field control.
In Objective-C:
[textField addTarget:self
...
postgresql COUNT(DISTINCT …) very slow
...
You can use this:
SELECT COUNT(*) FROM (SELECT DISTINCT column_name FROM table_name) AS temp;
This is much faster than:
COUNT(DISTINCT column_name)
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Multiple line code example in Javadoc comment
I have a small code example I want to include in the Javadoc comment for a method.
15 Answers
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warning: [options] bootstrap class path not set in conjunction with -source 1.5
...va
On UNIX systems, locate rt.jar using:
locate -r '/rt.jar$'
Set JAVA_HOME so that rt.jar is located at $JAVA_HOME/jre/lib/rt.jar, then:
javac -source 1.7 -bootclasspath "$JAVA_HOME/jre/lib/rt.jar" Main.java
Tested on Ubuntu 14.04 for Oracle Java 7 and 8.
...
Setting action for back button in navigation controller
...; Bool
}
extension UINavigationController {
public func navigationBar(_ navigationBar: UINavigationBar, shouldPop item: UINavigationItem) -> Bool {
// Prevents from a synchronization issue of popping too many navigation items
// and not enough view controllers or viceversa fr...
Types in Objective-C on iOS
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This is a good overview:
http://reference.jumpingmonkey.org/programming_languages/objective-c/types.html
or run this code:
32 bit process:
NSLog(@"Primitive sizes:");
NSLog(@"The size of a char is: %d.", sizeof(char));
NSLog(@"The size of short is: %d.", sizeof(short));
NSLog(@"The si...
Applying function with multiple arguments to create a new pandas column
...f = pd.DataFrame({"A": [10,20,30], "B": [20, 30, 10]})
>>> df['new_column'] = np.multiply(df['A'], df['B'])
>>> df
A B new_column
0 10 20 200
1 20 30 600
2 30 10 300
or vectorize arbitrary function in general case:
>>> def fx(x, y):
...
How can I automatically deploy my app after a git push ( GitHub and node.js)?
...ervice Hooks' => 'WebHook URLs'
and add
http://your-domain-name/git_test.php
then create git_test.php
<?php
try
{
$payload = json_decode($_REQUEST['payload']);
}
catch(Exception $e)
{
exit(0);
}
//log the request
file_put_contents('logs/github.txt', print_r($payload, TRUE), FILE...
Applications are expected to have a root view controller at the end of application launch
... make sure self.window is initialized like self.window = [[[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]] autorelease];
– Raptor
Feb 13 '12 at 12:07
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