快捷的方式找到文件中查找

Question

最大/最小/平均價值我在格式的文件

1 52 
2 456 
3 4516 
5 4545 
6  41 

會是什麼文件中讀取並獲得最大/最小/平均價值的最快方法在PHP的第二列？

Answer 1

類似於以下內容，其中<filename>是文件的路徑。

$file = fopen('<filename>', 'r'); 

$a = 0; 
$b = 0; 
$first = true; 
while (fscanf($file, '%d%d', $a, $b)) { 
    if ($first) 
    { 
     $min = $b; 
     $max = $b; 
     $total = $b; 
     $count = 1; 
     $first = false; 
    } 
    else 
    { 
     $total += $b; 
     if ($b < $min) $min = $b; 
     if ($b > $max) $max = $b; 
     $count++; 
    } 
} 
$avg = $total/$count; 

演示：http://ideone.com/rWbqm

Answer 2

從製造代碼@mellamokb一些性能改進：

$file = fopen('<filename>', 'r'); 

$a = $b = 0; 
if (fscanf($file, '%d%d', $a, $b)) 
{ 
    $min = $max = $total = $b; 
    $count = 1; 
    while (fscanf($file, '%d%d', $a, $b)) 
    { 
     $total += $b; 
     if ($b < $min) $min = $b; 
     else if ($b > $max) $max = $b; 
     ++$count; 
    } 
    $avg = $total/$count; 
} 
else 
{ 
    // Do something here as there is nothing in the file 
}