PHP¶

execution¶

php myphpfile.php

語法¶

extend¶

class inheritance¶

class¶

::¶

static function/variable in a class
可以直接 [classname]::[static function] 而不用先 instantiate class
https://www.php.net/manual/en/language.oop5.static.php

->¶

.

$this¶

狹義的 self ?

::class¶

return full name of a class including namespace

e.g.

namespace amogus {
    class ඞ {
    }
    echo ඞ::class; // amogus\ඞ
}

https://stackoverflow.com/a/42064777/15493213

protected¶

variables accessibly by the classes extending this class

magic functions¶

__contruct()¶

init function, auto run when created
public function __construct(){} = def __init__()

__invoke()¶

run when the class is called as a function

class tt
{
    public function __invoke($x)
    {
        print($x);
    }
}
$obj = new tt;
$obj(5); //will print 5

type hint¶

限定 function variable 為某 class
function sus(amogus $x){} 代表 for sus($blue)，$blue 只能是 amogus class，否則會噴 error *

class god{
    public function win(){
        print('i am not the imposter');
    }
}

class amogus{
    public function win(){
        print('sus sus sus sus ඞඞඞඞඞඞඞඞඞ sussy ඞඞඞ');
    }
}

function prevail(amogus $amigo){
    $amigo->win();
}

$red = new amogus();
$stopid = new god();
prevail($red); //good ඞඞ
prevail($stopid); //fatal error

=>¶

dictionary 的 :

closure¶

function(){}

namespace¶

when include others' code, may have variable name collision, thus use namespace to avoid

autoload¶

https://stackoverflow.com/a/7987085/15493213
先設個 spl_autoload_register() function，之後用別的 file 的 class 的時候，就會根據那個 function 自動去 include 省去把每個你要的 class 都手動 include 一遍的麻煩 *

spl_autoload_register(function ($class_name) {
    include $class_name . '.php';
});

$obj  = new MyClass1();
$obj2 = new MyClass2();

會自動 include MyClass1.php & MyClass2.php s.t. 你可以用各自檔案內的 class MyClass1() & MyClass2()

Use¶

Alias Something as Another¶

To alias something as another, you can use the use statement in PHP.

use App\model\Shop as Shop;

so the following two code snippets are equivalent:

use haha\hoho\bruh; 
$tf = new bruh;

$tf = new haha\hoho\bruh;

For more information, please refer to this Stack Overflow post.

trait¶

把 function 包起來，use 這個 trait in a class 就能用裡面的所有 function

trait message1 {
public function msg1() {
    echo "POOP is fun! ";
  }
}

class Welcome {
  use message1;
}

$obj = new Welcome();
$obj->msg1();

interface¶

弄一個 class 大致架構
interface → 如果不按著那個 interface 寫，就會跑 error

<?php
interface A
{
    public function foo();
}

interface B extends A
{
    public function baz(Baz $baz);
}

// This will work
class C implements B
{
    public function foo()
    {
    }

    public function baz(Baz $baz)
    {
    }
}

// This will not work and result in a fatal error
class D implements B
{
    public function foo()
    {
    }

    public function baz(Foo $foo)
    {
    }
}
?>

Unset¶

unset() is a function in PHP that deletes a variable and frees up memory. For more information, please refer to this Stack Overflow post.

&Variable¶

The & symbol in PHP is used to create a reference to a variable. Here's an example:

<?php
$number = 3;
$pointer = &$number;  // Sets $pointer to a reference to $number
echo $number."<br/>"; // Outputs  '3' and a line break
$pointer = 24;        // Sets $number to 24
echo $number;         // Outputs '24'
?>

For more information, please refer to this Stack Overflow post.

Curl¶

In PHP, curl_exec() is a function that executes a curl.

? :¶

The ? : syntax is known as the ternary operator in PHP. It is a shorthand way to write an if-else statement.

e,g,

$hola = $execute ? 'yes' : 'no';

=

if($execute){
  $hola = 'yes';
}else{
  $hola = 'no';
}

Date¶

To format dates in PHP, you can use the DateTime class. Here are some examples:

ISO 8601 Local Time¶

$datestr = '2021/7/30 10:33'; 
$date = new DateTime($datestr, new DateTimeZone('+0800')); $timestamp = $date->format('c'); //'U' for UTC echo $timestamp;

ISO 8601 UTC Z¶

$datestr = '2021/7/30 10:33

Running PHP Files¶

To run a PHP file, you can follow these steps:

Open XAMPP.
Start Apache.
Put your PHP file in the xampp/htdocs directory.
Go to http://localhost/test/bruh.php to run the xampp/htdocs/test/bruh.php file.

Display your php info¶

<?php
phpinfo();
?>

Timezones¶

Design Patterns¶

Dependency Injection¶

要使用一個東西時，把建立那個東西的 code 先寫好(e.g. 用 container)，要用的時候直接引用，這樣要更改建立那東西的步驟/參數時，直接改那套 code 就好，不用把每次建立並引用那東西的 code 都改一遍

You can learn more about dependency injection from the following resources:

Facade¶

把一堆雜亂的 code 包上一層皮，在外面蓋上很好 access 很乾淨的 API，regardless of how messy the interior is.

Facade Design Pattern in PHP 8