PHP 编程语言指南：PHP 语法入门

terry 2年前 (2023-09-25) 阅读数 53 #后端开发

1.啥也不说了，说`世界你好`第一：`echo的输出`

看起来很酷。 SpringBoot的HelloWorld比这个要省力很多

---->[Hello.php]---------------------------
<?php 
echo "Hello World!"; 
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2。变量 `$ 名称 = 变量`

---->[vartest.php]---------------------------
<?php
    $name="张风捷特烈";//生成变量
    echo $name;//输出变量
    echo "<br />";//输出换行
    $name="toly";//改变变量
    echo $name;//输出变量
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3。多种形式的数据组织

感觉比 JavaScript 更克制，比 Python 更克制一点。 $ 符号太多了...令人眼花缭乱

<?php

$t = true;//1.布尔型
$fa = false;//布尔型

$i = 5; //2.整型
$a = 0xff; // 支持十六进制数 -- 255
$b = 074; // 支持八进制数 -- 60

$f = 3.14159;//3.浮点型
$f1 = 3.14159e4;//浮点型 31415.9
$f2 = 3.14159e-3;//浮点型 0.00314159

$str = "String Type";//4.字符串
$str = 'String Type';//字符串

$color = array("red", "green", "blue");//5.数组
echo $color[0];//获取元素

$colorMap = array("red"=>"红色", "green"=>"绿色", "blue"=>"蓝色");//6.类似映射或字典
echo $colorMap["red"];//红色

$shape = new Shape("四维空间");//7.对象
echo $shape->getName(); //调用方法

$n=null;//8.null

class Shape{
    var $name;
    function __construct($name = "green"){
        $this->name = $name;
    }

    /**
     * @return string
     */
    public function getName() {
        return $this->name;
    }

    /**
     * @param string $name
     */
    public function setName($name){
        $this->name = $name;
    }
}
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4。请参阅请求和响应：`Hello.php`

|--- 客户端请求 (此时不太关心)
GET http://toly1994328.com/Hello.php HTTP/1.1
Host: toly1994328.com
Connection: keep-alive
Cache-Control: max-age=0
Upgrade-Insecure-Requests: 1
User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/70.0.3538.110 Safari/537.36
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8
Accept-Encoding: gzip, deflate
Accept-Language: zh-CN,zh;q=0.9

|--- 服务端响应 
HTTP/1.1 200 OK
Date: Wed, 13 Mar 2019 14:06:15 GMT
Server: Apache/2.4.23 (Win64) PHP/5.6.25
X-Powered-By: PHP/5.6.25
Content-Length: 13
Keep-Alive: timeout=5, max=100
Connection: Keep-Alive
Content-Type: text/html; charset=UTF-8  <----text/html 表示可以让浏览器解析请求体中的html代码

Hello World! <---- 可见echo可以将数据放入请求体里
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5。小测试一下

既然echo可以发布，那么如果放一个静态页面来发布会怎么样？我们来做一个粒子
这说明echo可以输出整个html页面供浏览器解析。在这种情况下，php的作用应该是控制服务器的输出流。

<?php
echo "<!doctype html>
<html>
<head>
    <meta charset=\"utf-8\">
    <title>液态粒子字体</title>
    <style>
        body,html {
            margin:0;
            width:100%;
            overflow:hidden;
        }
        canvas {
            width:100%;
        }
        .control {
            position:absolute;
        }
        .control input {
            border:0;
            margin:0;
            padding:15px;
            outline:none;
            text-align:center;
        }
        .control button {
            border:0;
            margin:0;
            padding:15px;
            outline:none;
            background:#333;
            color:#fff;
        }
        .control button:focus,.control button:hover {
            background:#222
        }
    </style>
</head>
<body>
<div class = \"control\" style = \"position:absolute\">
    <input type = \"text\" value = \"张风捷特烈\" id = \"t\">
    <button onclick = \"changeText(t.value)\">
        change
    </button>
</div>
<script>
    var can = document.createElement(\"canvas\");
    document.body.appendChild(can);
    var ctx = can.getContext('2d');
    function resize(){
        can.width = window.innerWidth;
        can.height = window.innerHeight;
    }
    const max_radius = 3;
    const min_radius = 1;
    const drag = 50;
    window.onresize = function(){
        resize();
    };
    function cfill(){
        ctx.fillStyle = \"#000\";
        ctx.fillRect(0,0,can.width,can.height);
        ctx.fill();
    }
    var mouse = {
        x:-1000,
        y:-1000
    };
    can.onmousemove = function(e){
        mouse.x = e.clientX;
        mouse.y = e.clientY;
    };
    can.ontouchmove = function(e){
        mouse.x = e.touches[0].clientX;
        mouse.y = e.touches[0].clientY;
    };
    resize();
    cfill();

    function distance(x,y,x1,y1){
        return Math.sqrt( ( x1-x ) * ( x1-x ) + ( y1-y ) * ( y1-y ) );
    }
    class Particle{
        constructor(pos,target,vel,color,radius){
            this.pos = pos;
            this.target = target;
            this.vel = vel;
            this.color = color;
            this.radius = radius;
            var arr = [-1,1];
            this.direction = arr[~~(Math.random()*2)]*Math.random()/10;
        }
        set(type,value){
            this[type] = value;
        }
        update(){
            this.radius += this.direction;
            this.vel.x = (this.pos.x - this.target.x)/drag;
            this.vel.y = (this.pos.y - this.target.y)/drag;
            if(distance(this.pos.x,this.pos.y,mouse.x,mouse.y) < 50){
                this.vel.x += this.vel.x - (this.pos.x - mouse.x)/15;
                this.vel.y += this.vel.y - (this.pos.y - mouse.y)/15;
            }
            if(this.radius >= max_radius){
                this.direction *= -1;
            }
            if(this.radius <= 1){
                this.direction *= -1;
            }
            this.pos.x -= this.vel.x;
            this.pos.y -= this.vel.y;
        }
        draw(){
            ctx.beginPath();
            ctx.fillStyle = this.color;
            ctx.arc(this.pos.x,this.pos.y,this.radius,0,Math.PI*2);
            ctx.fill();
        }
    }
    var particles = [];
    var colors = [\"#bf1337\",\"#f3f1f3\",\"#084c8d\",\"#f2d108\",\"#efd282\"];
    var bool = true;
    var current = 0,i;
    function changeText(text){
        var current = 0,temp,radius,color;
        cfill();
        ctx.fillStyle = \"#fff\";
        ctx.font = \"120px Times\";
        ctx.fillText(text,can.width*0.5-ctx.measureText(text).width*0.5,can.height*0.5+60);
        var data = ctx.getImageData(0,0,can.width,can.height).data;
        cfill();
        for(i = 0;i < data.length;i += 8){
            temp = {x:(i/4)%can.width,y:~~((i/4)/can.width)};
            if(data[i] !== 0 && ~~(Math.random()*5) == 1/*(temp.x % (max_radius+1) === 0 && temp.y % (max_radius+1) === 0)*/){
                if(data[i+4] !== 255 || data[i-4] !== 255 || data[i+can.width*4] !== 255 || data[i-can.width*4] !== 255){
                    if(current < particles.length){
                        particles[current].set(\"target\",temp);
                    }else{
                        radius = max_radius-Math.random()*min_radius;
                        temp = {x:Math.random()*can.width,y:Math.random()*can.height};
                        if(bool){
                            temp = {x:(i/4)%can.width,y:~~((i/4)/can.width)};
                        }
                        color = colors[~~(Math.random()*colors.length)];
                        var p = new Particle(
                            temp,
                            {x:(i/4)%can.width,y:~~((i/4)/can.width)},{x:0,y:0},
                            color,
                            radius);
                        particles.push(p);
                    }
                    ++current;
                }
            }
        }
        bool = false;
        particles.splice(current,particles.length-current);
    }
    function draw(){
        cfill();
        for(i = 0;i < particles.length;++i){
            particles[i].update();
            particles[i].draw();
        }
    }
    changeText(\"张风捷特烈\");
    setInterval(draw,1);</script>
</body>
</html>"
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