而循環VS的foreach循環

Question

我試着將其打印在Excel中，但我不明白爲什麼foreach循環給我一個警告：非法串偏移但while循環它只是平穩運行

這是while循環

EDITED

include 'db.php'; 
$sql = "SELECT * FROM customer"; 
$result = mysql_query($sql); 
$excel = array(); 

while($row = mysql_fetch_array($result)){ 
    $wew = $row["fname"]."\t".$row["lname"]."\t".$row["email"]; 
    array_push($excel,$wew); 
} 

echo implode("\n",array_values($excel)); 

這是我foreach循環

include 'db.php'; 
$sql = "SELECT * FROM customer"; 
$result = mysql_query($sql); 
$row = mysql_fetch_array($result); 
$excel = array(); 

foreach($row as $r){ 
    $wew = $r["fname"]."\t".$r["lname"]."\t".$r["email"]; 
    array_push($excel,$wew); 
} 

echo implode("\n",array_values($excel)); 

我試着去了解它，但怎麼也找不到解決這個問題之一。

Answer 1

你$r是string型，而不是array這樣的：

foreach($row as $r){ 
    $wew = $row["fname"]."\t".$row["lname"]."\t".$row["email"]; 
    array_push($excel,$wew); 
} 

OR

$wew = ""; 
foreach($row as $r){ 
    $wew .= $row["fname"]."\t".$row["lname"]."\t".$row["email"]; 
} 
array_push($excel,$wew);