PHP 字符串比较。正则表达式

Question

我们正在尝试显示文件是否包含特定字符串：

这里我们读取文件：

$myFile = "filename.txt";
$fh = fopen($myFile,'r');
$theData = fread($fh, filesize("filename.txt"));
fclose($fh);

文件名.txt 包含“离线”

这里我们尝试比较字符串：

if(strcmp($theData,"Online")==0){
echo "Online"; }
elseif(strcmp($theData,"Offline")==0) {
echo "Offline"; }
else {
echo "This IF is not working." }

我们尝试过使用常规 if 而不使用 strcomp，但它也不起作用。我认为 IF 无法将 fread 的结果与常规字符串进行比较。也许我们需要尝试另一种方法。

有任何想法吗？

Answer 1

使用preg_match()

$string = "your-string";
$pattern = "/\boffline\b/i"; 

// The \b in the pattern indicates a word boundary, so only the distinct 
// word "offline" is matched; if you want to match even partial word "offline"
// within some word, change the pattern to this /offline/i

if(preg_match($pattern, $string)) {
    echo "A match was found.";
}

strpos()您也可以使用（在这种情况下速度更快）

$string = 'your-stringoffline';
$find   = 'offline';
$pos = strpos($string, $find);

if($pos !== false){
    echo "The string '$find' was found in the string '$string' at position $pos";
}else{
    echo "The string '$find' was not found in the string '$string'";
}