16/2/22
赋值运算
<span>1</span><span>$a</span> = "cmflovehxc"<span>; </span><span>2</span><span>$b</span>=<span>$a</span><span>; </span><span>3</span><span>$c</span>=&<span>$a</span><span>; </span><span>4</span><span>$a</span> = "cmflovehxc"<span>; </span><span>5</span><span>6</span><span>echo</span><span>$b</span>."<br />"<span>; </span><span>7</span><span>echo</span><span>$c</span>;
(1)“=”：把右边表达式的值赋给左边的运算数。它将右边表达式值复制一份，交给左边的运算数。换而言之，首先给左边的运算数申请了一块内存，然后把复制的值放到这个内存中。
相当于JS的等于号。变量赋值；两个变量是两个不同的堆内存。
(2)“=&”：引用赋值，意味着两个变量都指向同一个数据。它将使两个变量共享一块内存，如果这个内存存储的数据变了，那么两个变量的值都会发生变化。
两个变量是两个相同的堆内存。
常量
<span> 1</span><span>define</span>("PI1",3.14<span>);
</span><span> 2</span><span>$p</span> = "PI1"<span>;
</span><span> 3</span><span>echo</span><span>$p</span>;<span>//</span><span>PI1</span><span> 4</span><span>echo</span><span>constant</span>(<span>$p</span>);<span>//</span><span>3.14</span><span> 5</span><span>if</span>(<span>defined</span>(<span>$p</span>)==<span>true</span><span>){
</span><span> 6</span><span>echo</span> '111'<span> ;
</span><span> 7</span> }<span>else</span><span>{
</span><span> 8</span><span>echo</span> '222'<span>;
</span><span> 9</span><span>}
</span><span>10</span><span>//</span><span>返回111<br />11 //constant（）与defined（）都有一种翻译功能<br /></span>以上就介绍了php学习代码杂记，包括了方面的内容，希望对PHP教程有兴趣的朋友有所帮助。
PHP怎么学习？PHP怎么入门？PHP在哪学？PHP怎么学才快？不用担心，这里为大家提供了PHP速学教程(入门到精通)，有需要的小伙伴保存下载就能学习啦！
Copyright 2014-2025 https://www.php.cn/ All Rights Reserved | php.cn | 湘ICP备2023035733号
619
收藏
