My PHP Notes

Learnd from Codecademy

Several functions

strlen $length = strlen($example);
substr $subString = substr($example, 0, 4); // 0 is starting position; 4 is length
strtoupper $uppercase = strtoupper($example);
strtolower the same with 3
strpos $position = strpos($example, "q");
M_PI a PHP constant that is equal to pi
round $integerNum = round($floatNum); $twoDecimalPlaces = round($floatNum, 2);
rand print rand(); // prints a number between 0 and 32767 print rand(1, 10); // prints a number between 1 and 10
array $anArray = array();
array_push array_push($anArray, "item");
count count($anArray); // return the number of elements of the array
sort sort($anArray); // sequense from small to big
rsort rsort($anArray); // sequense from big to small
join join(",", $anArray); // make an array into a string, splited by ","

Object Oriented PHP

<!DOCTYPE html>
<html>
    <head>
      <title> Introduction to Object-Oriented Programming </title>
      <link type='text/css' rel='stylesheet' href='style.css'/>
    </head>
	<body>
      <p>
      <?php
        // The code below creates the class
        class Person {
            // Creating some properties (variables tied to an object)
            public $isAlive = true;
            public $firstname;
            public $lastname;
            public $age;

            // Assigning the values
            public function __construct($firstname, $lastname, $age) {
              $this->firstname = $firstname;
              $this->lastname = $lastname;
              $this->age = $age;
            }

            // Creating a method (function tied to an object)
            public function greet() {
              return "Hello, my name is " . $this->firstname . " " . $this->lastname . ". Nice to meet you! :-)";
            }
          }

        // Creating a new person called "boring 12345", who is 12345 years old ;-)
        $me = new Person('boring', '12345', 12345);

        // Printing out, what the greet method returns
        echo $me->greet();
        ?>
        </p>
    </body>
</html>

Create a new class class Person {}
Construct an instance of the class $instance = new Person();
print a public property from a class

class Person {
  public $theValue = true;
}

$example = new Person();

print $example->theValue; // true

methods: functions bundled into objects

class Person {
  public function __construct($para1, $para2) {
    this->num1 = $para1;
    this->num2 = $para2;
  }
}
$obj = new Person("one", "two");
print $obj->num1; // one

OOP PHP

class Person {
  function __construct($name) {
      $this->name = $name;
  }

  public function dance() {
    return "I'm dancing!";
  }
}

is_a(): find out if a particular object is an instance of a given class

if (is_a($me, "Person")) {
  echo "I'm a person";
}

property_exists(): if an object has a given property

if (property_exists($me, "name")) {
  echo "I have a name";
}

method_exists(): if an object has a given method

if (method_exists($me, "dance")) {
  echo "I know how to dance";
}

inheritance

class Shape {
  public $hasSides = true;
}

class Square extends Shape {
}

override and the final word

class Vehicle {
    final public function honk() {
      return "HONK HONK!";
    }
  }

  class Bicycle extends Vehicle {
      public function honk() {
          return "Beep beep!";    
      }
  }

  $bicycle = new Bicycle();

  echo $bicycle->honk(); // Cannot override final method Vehicle::honk()

?>

const is short for constant, which is not allowed to change

class Immortal extends Person {
  // Immortals never die!
  const alive = true;
}

Scope Resolution 范围解析符 ::

class Person {
  const life = "MAXIMUM";
}

echo Person::life; //MAXIMUM

static is similar with const, but it can be a function for a class

arrays

$anArray = array(0, 'apple', '333');
echo $anArray[0]; // 0
Associative Arrays

$anotherArray = array('color' => 'blue',
                       'sex' => 'male',
                       'year' => 2016);
echo $anotherArray['color']; // blue

Iterating over Associative Arrays

$salad = array('lettuce' => 'with',
               'tomato' => 'without',
               'onions' => 'with');

foreach ($salad as $key => $value) {
  echo $value . ' ' . $key; // with lettuce without tomato with onions
}

Multidimensional Arrays

$deck = array(array('2 of Diamonds', 2),
                  array('5 of Diamonds', 5),
                  array('7 of Diamonds', 7));

echo 'You have the ' . $deck[2][1] . '!'; // You have the 7!
echo 'You have the ' . $deck[2] . '!'; // You have the Array!

Several functions

Object Oriented PHP

OOP PHP

arrays

目录

文章分类

友情链接