如何将文本输入写入文件中的新行

Question

这是我的代码，我希望从新行的文本字段中输入。例如，如果输入文本是名字和姓氏，那么我希望姓氏在新行上，并且我只有一个文本字段。我该怎么做？

 if (isset($string) and (bool)preg_match('/[A-Z]/', $string) == TRUE) {
    //if yes, it is writing it into file
    $myfile = fopen("names.txt", "w") or die("Unable to open file!");
    $txt = $string;
    fwrite($myfile, $txt);
    fclose($myfile);
    }
    else {
        echo "Sorry, your name is not in correct format.";
    }

Answer 1

也许这个解决方案是正确的

$names = [
    's34S$2 John',
    'John James Smith',
    'stack overflow',
    'John Smith',
    'John Johnson',
    'JohnWilliams',
    'Stack Best Overflow',
    'Smith'
];
$delimiter = 'n'; // "n" for real use
foreach($names as $name){
    $newName = preg_replace(
        '/^([A-Z][a-z]+([ ][A-Z][a-z]+)*)([ ][A-Z][a-z]+)+$/',
        "$1$delimiter$3",
        $name
    );
    if ( $newName != $name ){
        echo "'$name' => '$newName'n";
        // file_put_contents("names.txt", $newName); for real use
    } else {
        echo "'$name' =>  Sorry, your name is not in correct format.n";
    }
}

输出：

's34S$2 John' =>  Sorry, your name is not in correct format.
'John James Smith' => 'John Jamesn Smith'
'stack overflow' =>  Sorry, your name is not in correct format.
'John Smith' => 'Johnn Smith'
'John Johnson' => 'Johnn Johnson'
'JohnWilliams' =>  Sorry, your name is not in correct format.
'Stack Best Overflow' => 'Stack Bestn Overflow'
'Smith' =>  Sorry, your name is not in correct format.