PHP_EOL:
代表php的換行符，這個(gè)變量會(huì)根據(jù)平臺(tái)而變，在windows下會(huì)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語(yǔ)句過(guò)于冗長(zhǎng)，提高程序可讀性；

<?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:

1. 數(shù)值數(shù)組： array with index;
2. 關(guān)聯(lián)數(shù)據(jù)： array with key (actually dictionry);
3. 多維數(shù)據(jù)： contains 1+ array as elements;

<?php 
    $cars = array("Volvo", "BMW", "Toyota");
    $age = array("Peter"=>"35", "Ben"=>"37", "Joe"=>"43");

超級(jí)全局變量