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How does the Brainfuck Hello World actually work?
...
1. Basics
To understand Brainfuck you must imagine infinite array of cells initialized by 0 each.
...[0][0][0][0][0]...
When brainfuck program starts, it points to any cell.
...[0][0][*0*][0][0]...
If you move pointer right > you are moving pointer from cell X to cell X+1
.....
Android: How to bind spinner to custom object list?
...how I did it:
Just create your Spinner the usual way
Define 2 equal size arrays in your array.xml file -- one array for labels, one array for values
Set your Spinner with android:entries="@array/labels"
When you need a value, do something like this (no, you don't have to chain it):
String sel...
GET URL parameter in PHP
...
$_GET is not a function or language construct—it's just a variable (an array). Try:
<?php
echo $_GET['link'];
In particular, it's a superglobal: a built-in variable that's populated by PHP and is available in all scopes (you can use it from inside a function without the global keyword).
S...
What does “O(1) access time” mean?
...to the number of items in the collection.
Typical examples of these are arrays, which can be accessed directly, regardless of their size, and linked lists, which must be traversed in order from the beginning to access a given item.
The other operation usually discussed is insert. A collection c...
How to use NSJSONSerialization
...
Your root json object is not a dictionary but an array:
[{"id": "1", "name":"Aaa"}, {"id": "2", "name":"Bbb"}]
This might give you a clear picture of how to handle it:
NSError *e = nil;
NSArray *jsonArray = [NSJSONSerialization JSONObjectWithData: data options: NSJSONRe...
Difference between class and type
...
A class is a type. An interface is a type. A primitive is a type. An array is a type.
Therefore, every type is also either a class (including an enum constant), an interface, a primitive, or an array.
There are two distinct categories of types: primitive types and reference types:
A variab...
Accessing nested JavaScript objects and arays by string path
...e:
function resolve(path, obj=self, separator='.') {
var properties = Array.isArray(path) ? path : path.split(separator)
return properties.reduce((prev, curr) => prev && prev[curr], obj)
}
Example usage:
// accessing property path on global scope
resolve("document.body.style.w...
Why does [5,6,8,7][1,2] = 8 in JavaScript?
...
[1,2,3,4,5,6][1,2,3];
^ ^
| |
array + — array subscript access operation,
where index is `1,2,3`,
which is an expression that evaluates to `3`.
The second [...] cannot be an array, so it’s an array subsc...
Best practices/performance: mixing StringBuilder.append with String.concat
....toString();
concat()
String s = s1.concat(s2);
String creates char[] array that can fit both s1 and s2. Copies s1 and s2 contents to this new array. Actually requires less work then + operator.
StringBuilder.append()
Maintains an internal char[] array that grows when needed. No extra char[] ...
How do you convert a byte array to a hexadecimal string, and vice versa?
How can you convert a byte array to a hexadecimal string, and vice versa?
45 Answers
4...