2018-06-21

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:

1. 数值数组： array with index;
2. 关联数据： array with key (actually dictionry);
3. 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