PHP_EOL:
代表php的换行符，这个变量会根据平台而变，在windows下会是/r/n，在linux下是/n，在mac下是/r;
<?php
$test = 'string from mark';
$username = isset($test) ? $test : 'nobody';
echo $username, PHP_EOL;
switch statement: 避免if语句过于冗长，提高程序可读性；
<?php
$favcolor = 'red';
switch ($favcolor) {
case 'red':
echo 'Your favorite color is red!';
break;
case 'blue':
echo 'Your favorite color is blue!';
break;
case 'green':
echo 'Your favorite color is green!';
break;
default:
echo 'Your favorite color is neither red, blue, or green!';
}
array:
- 数值数组： array with index;
- 关联数据： array with key (actually dictionry);
- 多维数据： contains 1+ array as elements;
<?php
$cars = array("Volvo", "BMW", "Toyota");
$age = array("Peter"=>"35", "Ben"=>"37", "Joe"=>"43");
超级全局变量
| 变量名 | 作用 |
|---|---|
| $GLOBALS | |
| $_SERVER | |
| $_REQUEST | |
| $_POST | |
| $_GET | |
| $_FILES | |
| $_ENV | |
| $_COOKIE | |
| $_SESSION |
