PHP 删除重复空格

Question

为什么这不起作用？

$content=file_get_contents('whatever.txt');
$content=str_replace("\r\n","\n",$content); // Convert linebreaks
$content=str_replace("\n",' ',$content); // Remove linebreaks
$content=preg_replace('/\s+/',' ',$content); // Remove all duplicate spaces
$content=preg_replace('/[^a-zA-Z\s]/','',$content); // Remove all non-letters
$content=trim($content);
$content=explode(' ',$content);

有些值仍然是空白：

例如

$content[123] = '';

我是否理解错误？肯定应该没有吧？

Answer 1

我认为整个事情可以总结/修正为以下几行：

$content = file_get_contents('whatever.txt'); // Get file
$content = preg_replace('/[^a-zA-Z\s]/', '', $content); // Strip non-alpha/whitespace
$content = preg_split('/\s+/', $content, NULL, PREG_SPLIT_NO_EMPTY); // Split by whitespace and remove empty elements