PHP基础
1. 输出 echo 或 print
<?php echo "hello"; ?>
<?php echo 13*123; ?>
<?php print "hello"; ?>
2. 变量，$开头
<?php $myVariable=0 ; ?>
3 . 注释 : // 同 c, java
4. if else elseif: 基本同C Java, 但是elseif连写
if () {} elseif () {} else {}
5. 数组 array
$items=array("apple","banana"); //创建数组 echo $items[2];// 输出数组元素 unset($items); unset($items[2]);// 删除元素或整个数组
array_push($items,"pig"); // push
count($items);// count
sort($items); // sort
associative array： 类似于python的字典，c++的map
$myAssocArray = array('year' => 2012, 'colour' => 'blue', 'doors' => 5); echo $myAssocArray['colour'];//输出
using for each in associative array
$food=array("apple"=>"yes","banana"=>"no","pig"=>"yes"); foreach($food as $f =>$isYes) { echo $isYes. ' '.$f.'<br >'; }
6. for 循环：同C Java
7. foreach
$items= array("JavaScript", "HTML/CSS", "PHP","Python","Ruby"); foreach ($items as $i) { echo "<li>$i</li>"; }
8. while/ do while： 同 C Java
9. 函数 function
function foo($pa1, $pa2) { return "xx"; }
10. 类 class
class Person { public $name; public $age; public function __construct($na)//构造函数 { $this->name=$na;//访问成员变量前不加"$" } } $student=new Person("student");//创建实例
is_a($me, "Person");// 判断是否是某个类 property_exists($me, "name");// 判断是否有某个property method_exists($me, "dance");// 判断是否有某个method
class Person { public static function say()// 静态函数 { echo "Hello!"; } const name="xxx";//常量 } Person::say(); Person::name;//调用静态函数和常量
11. triple equal
double equal only compare value but ignore type
triple equal will compare both
<?php $num1 = "1"; $num2 = 1; if ($num1 === $num2){ echo "type and value equal"; } elseif($num1 == $num2){ echo "value equal"; } ?>