为什么我的变量在函数内部未定义

Question

It gives me this error Notice: Undefined variable: newfile and of course it also gives me fwrite() expects parameter 1 to be resource, null given cause of the first error. What I doing wrong?

$file = fopen("mycsv.csv", 'r');
$newfile = fopen("myjson.txt", 'w');

function write($text, $tab) {
    $tabs = "";
    for ($index = 0; $index < $tab; $index++) {
        $tabs .= "\t";
    }
    fwrite($newfile, $text."
".$tabs); //error here
}

Answer 1

Have a read about variable scope in the manual

$file and $newfile are global, therfore $newfile cannot be accessed locally in your function. Either move it into the function, pass it in as a parameter or as a last resort declare it as global in the function