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The difference between empty and isset toner empty running on empty textutils.isempty

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Release: 2016-07-29 08:48:47
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I have never understood these two functions very well. I will write a small program to deepen my understanding!

empty是什么意思啊,err empty response,isempty,empty音译歌词,empty sky,empty winner,empty怎么读,empty 台式电脑,empty string,php empty,empty的反义词,isempty函数,toner empty,running on empty,textutils.isempty

<?<span>php

</span><span>/*</span><span>*
*    isset  &mdash; 检测变量是否设置
*    如果 变量 存在则返回 true, 否则返回 false
*
*    empty  &mdash; 检查一个变量是否为空
*    如果 变量 是非空或非零的值,则 empty() 返回 false
*</span><span>*/</span><span>$is_var</span> = ''<span>;

</span><span>if</span>(<span>isset</span>(<span>$is_var</span><span>)) {
    </span><span>echo</span> "变量存在!<br />"<span>;
} </span><span>else</span><span> {
    </span><span>echo</span> "变量不存在!<br />"<span>;
}

</span><span>if</span>(<span>empty</span>(<span>$is_var</span><span>)) {
    </span><span>echo</span> "变量为空!<br />"<span>;
} </span><span>else</span><span> {
    </span><span>echo</span> "变量不为空!<br />"<span>;
}

</span>?>
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empty是什么意思啊,err empty response,isempty,empty音译歌词,empty sky,empty winner,empty怎么读,empty 台式电脑,empty string,php empty,empty的反义词,isempty函数,toner empty,running on empty,textutils.isempty

Output result:

The variable exists!
The variable is empty!

The above has introduced the difference between empty and isset, including the content of empty. I hope it will be helpful to friends who are interested in PHP tutorials.

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