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Do declared properties require a corresponding instance variable?
...des your getter/setter for you. The auto-coder setter initializes integers and floats to zero, for example. IF you declare an instance variable, and DO NOT specify a corresponding @property, then you cannot use @synthesize and must write your own getter/setter.
You can always override the auto-cod...
Shards and replicas in Elasticsearch
I am trying to understand what shard and replica is in Elasticsearch, but I didn't manage to understand it. If I download Elasticsearch and run the script, then from what I know I have started a cluster with a single node. Now this node (my PC) have 5 shards (?) and some replicas (?).
...
What is the difference between statically typed and dynamically typed languages?
... advantage here is that all kinds of checking can be done by the compiler, and therefore a lot of trivial bugs are caught at a very early stage.
Examples: C, C++, Java, Rust, Go, Scala
Dynamically typed languages
A language is dynamically typed if the type is associated with run-time values, and ...
When should I use a trailing slash in my URL?
...misused.
Basically the URL format came from the same UNIX format of files and folders, later on, on DOS systems, and finally, adapted for the web.
A typical URL for this book on a Unix-like operating system would be a file path such as file:///home/username/RomeoAndJuliet.pdf, identifying the e...
How do MySQL indexes work?
...at's where the name came from):
Let's say you have a book about databases and you want to find some information about, say, storage. Without an index (assuming no other aid, such as a table of contents) you'd have to go through the pages one by one, until you found the topic (that's a full table s...
Clear icon inside input text
...d browsers
If you need IE9 support here are some workarounds
Using a standard <input type="text"> and some HTML elements:
/**
* Clearable text inputs
*/
$(".clearable").each(function() {
var $inp = $(this).find("input:text"),
$cle = $(this).find(".clearable__clear")...
What does the caret operator (^) in Python do?
I ran across the caret operator in python today and trying it out, I got the following output:
5 Answers
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How to instantiate non static inner class within a static method?
...).
If you make your inner class "static" then there is no hidden pointer and your inner class cannot reference members of the outer class. A static inner class is identical to a regular class, but its name is scoped inside the parent.
Here is a snippet of code that demonstrates the syntax for cre...
LISTAGG in Oracle to return distinct values
...
19c and later:
select listagg(distinct the_column, ',') within group (order by the_column)
from the_table
18c and earlier:
select listagg(the_column, ',') within group (order by the_column)
from (
select distinct the_colum...
First-time database design: am I overengineering? [closed]
I'm a first year CS student and I work part time for my dad's small business. I don't have any experience in real world application development. I have written scripts in Python, some coursework in C, but nothing like this.
...