Commonly used array functions in php (4) (whether there is a certain key name or index in the array)

<span style="color: #008000">/*</span><span style="color: #008000">**********array_key_exists(检查键名或索引是否在数组中)****************</span><span style="color: #008000">*/</span>
<span style="color: #800080">$arr1</span> = <span style="color: #0000ff">array</span>('name' => 'Sheldon', 'age' => 30, 'address' => 'Carlifornia'<span style="color: #000000">);
</span><span style="color: #0000ff">if</span> (<span style="color: #008080">array_key_exists</span>('name', <span style="color: #800080">$arr1</span><span style="color: #000000">)) {
    </span><span style="color: #0000ff">echo</span> 'the name element is in the array.'<span style="color: #000000">;
} </span><span style="color: #0000ff">else</span><span style="color: #000000"> {
    </span><span style="color: #0000ff">echo</span> 'name elment not exist.'<span style="color: #000000">;
}</span>

Check if there is a key named 'name' in $arr1.

Also check the numerical index.