爆炸到PHP陣列

Question

我正在處理這個程序，在這裏我試圖分開字符串電子郵件，由'，'，然後我存儲在數組中，然後在'foreach'中追加'city' ..

$email='aa,bb,cc,dd'; 
$a=explode(',',$email); 
//echo $a[2]; 
$result=""; 
foreach($a as $v) 
{ 
    $result .= " city = '$v' "; 
    echo $result; 
} 

我得到的結果作爲

city = 'aa' city = 'aa' city = 'bb' city = 'aa' city = 'bb' city = 'cc' city = 'aa' city = 'bb' city = 'cc' city = 'dd' 

，但我希望它是,,

city = 'aa' city = 'bb' city = 'cc' city = 'dd' 

是我的代碼錯了嗎？..請指導我..

Answer 1

將echo移出循環，因爲您正在循環中構建整個字符串，每次都會回顯字符串。

$result=""; 
foreach($a as $v) 
{ 
    $result .= " city = '$v' "; 

} 

    echo $result; // move it here 

Answer 2

你所得到的結果，按您的代碼，你echo結果在每個loop執行。

所以爲了得到$ result中的最終值，echo它在loop之外。

foreach($a as $v) 
{ 
    $result .= " city = '$v' "; 
} 
echo $result; 

Answer 3

的結果

$email='aa,bb,cc,dd'; 
$a=explode(',',$email); 
//echo $a[2]; 
$result=""; 
foreach($a as $v) 
{ 
    $result = " city = '$v' ";//changed $result .= " city = '$v' "; to $result = " city = '$v' "; 
    echo $result; 
} 

Answer 4

刪除字符串連接您的迴音$ rresult中的foreach所以你的字符串或變量是重複的。請嘗試以下代碼：

$email='aa,bb,cc,dd'; 
$a=explode(',',$email); 

$result=""; 
foreach($a as $v) 
{ 
    $result .= " city = '$v' ";  
} 
echo $result; 

Answer 5

刪除字符串concate ..

$email='aa,bb,cc,dd'; 
$a=explode(',',$email); 
//echo $a[2]; 
$result=""; 
foreach($a as $v) 
{ 
    $result = " city = '$v' "; // remove string concate.. 
    echo $result; 
} 

另一種方法是foreach循環外回聲......

$email='aa,bb,cc,dd'; 
$a=explode(',',$email); 
//echo $a[2]; 
$result=""; 
foreach($a as $v) 
{ 
    $result .= " city = '$v' "; 
} 

echo $result; // echo outside the foreach loop 

輸出

city = 'aa' city = 'bb' city = 'cc' city = 'dd'