PHP用空格分割文本为数组的方法

1 字段1 字段2 
2 字段1 字段2 
3 字段1 字段2 
4 字段1 字段2

<?php 
$file = fopen("text.txt", "r") or exit("Unable to open file!"); 
while(!feof($file))   
{   
    $arr = split(' ' , fgets($file)); 
    print_r($arr); 
} 
fclose($file); 
?>

Array 
( 
    [0] => 1 
    [1] => 字段1 
    [2] => 字段2 
 
) 
Array 
( 
    [0] => 2 
    [1] => 字段1 
    [2] => 字段2 
 
) 
Array 
( 
    [0] => 3 
    [1] => 字段1 
    [2] => 字段2 
 
) 
Array 
( 
    [0] => 4 
    [1] => 字段1 
    [2] => 字段2 
)