PHP学习笔记-数组(1)，php学习笔记数组

<?<span>php
</span><span>//</span><span>设置某个变量为一个空数组</span>
    <span>$arr</span>=<span>array</span><span>();
</span>?>

<?<span>php
    </span><span>$num</span>=<span>array</span>(1,2,3<span>);
    </span><span>print_r</span>(<span>$num</span>[0<span>]);
</span>?>

<?<span>php
</span><span>$arr</span>[0]=1;<span>//</span><span>方法1</span>
<span>$arr</span>=<span>array</span>('0'=>1);<span>//</span><span>方法2</span>
<span>$arr</span>=<span>array</span>(1);<span>//</span><span>方法3</span>
?>

<?<span>php
</span><span>//</span><span>从数组变量$arr中，读取键为0的值</span>
<span>$arr</span> = <span>array</span>(1,2,3<span>);
</span><span>$arr0</span>=<span>$arr</span>[0<span>];
</span><span>echo</span> <span>$arr0</span><span>;
</span>?>