bestyu

快速学习PHP基础语法

<?php 
    //变量
    $hello="hello world\n";
    echo $hello;
    echo "<br>";
    //输出类型
    var_dump($hello);
?>

几种不同的输出

<?php 
    $arr=array("S"=>'s',"HELLO");
    var_dump($arr);//array(2) { ["S"]=> string(1) "s" [0]=> string(5) "HELLO" } 
    echo $arr;//Array
    print_r($arr);//Array ( [S] => s [0] => HELLO ) 
    echo $arr['S'].' '.$arr[0];//s HELLO
?>

多维数组

<?php 
    $arr=array(array("S"=>'s',"HELLO"),array(1,2,3));
    $arr1=[[1,2,3],[5,6]];//另一种定义
    print_r($arr);
    //Array ( [0] => Array ( [S] => s [0] => HELLO ) [1] => Array ( [0] => 1 [1] => 2 [2] => 3 ) )
?>

foreach

<?php 
    $arr=['a'=>1,'b'=>5];
                    //键 : 值
    foreach($arr as $i=>$value){
        echo $i.' '.$value;
        echo "<br>";
    }
    // a 1
    // b 5    
?>

判断

if-else
if-elseif -else
money&&time?"travel":"stay at home"
switch{
    case 0: dosomething; break;  
    case 1: dosomething; break;
    default dosomething;
}    
match;

函数

<?php 
    function f($a,$b){
        echo $a+$b;
        echo "<br>";
        return "hello";
    }
    // 3
    // hello
    echo f(1,2);
?>