php - 如何检查 PHP 中的文本文件是否为空？

Question

PHP如何判断文本文件是否为空？

我试过我在互联网上找到的是这样的:

if( '' != filesize('data.txt')){

    echo "The file is empty";
}

还有这个:

if( 0 != filesize('data.txt')){

    echo "The file is empty";
}

而且它们似乎都不起作用。

Answer 1

首先简单地使用它:

if (filesize('data.txt') == 0){
    echo "The file is DEFINITELY empty";
}

如果仍有疑问(取决于 empty 对您的意义)，也可以尝试:

if (trim(file_get_contents('data.txt')) == false) {
    echo "The file is empty too";
}

注意 Niels Keurentjes，注意 http://php.net/manual/en/function.empty.php说:

Prior to PHP 5.5, empty() only supports variables; anything else will result in a parse error. In other words, the following will not work: empty(trim($name)). Instead, use trim($name) == false.