如何将这个条件重写为一个条件而不是两个嵌套的条件 - How do I rewrite this conditional as one conditional instead of two nested ones?

How do I rewrite this conditional as one conditional instead of two nested ones?

我正在努力读完一本书& &;我正在读第二章，所以我想这部分应该不会太难，但是我想不出来。

它希望我将这部分重写为一个条件而不是两个嵌套的条件-它还提示我必须使用AND操作符-:

if (isset($_REQUEST['gender'])) {
  $gender = $_REQUEST['gender'];
  if ($gender == 'M') {
    echo '<p><b>Good day, Sir!</b></p>';
  } elseif ($gender == 'F') {
  echo '<p><b>Good day, Madam!</b></p>';
  } else { // Unacceptable Value.
    $gender = NULL;
    echo '<p class="error">Gender should be either "M" or "F"!</p>';
  }
} else { // $_REQUEST['gender'] is not set.
  $gender = NULL;    
  echo '<p class="error">You forgot to select your gender!</p>';  
}

这是我使用的解决方案:

if (isset($_REQUEST['gender']) && $_REQUEST['gender']=='M'){
$gender = $_REQUEST['gender'];
echo '<p><b>Good day, Sir!</b></p>';
}
elseif (isset($_REQUEST['gender']) && $_REQUEST['gender']=='F'){
$gender = $_REQUEST['gender'];
echo '<p><b>Good day, Madam!</b></p>';
}
else{
$gender = NULL;
echo '<p class="error">You forgot to select your gender!</p>';  
}

if (!isset($_REQUEST['gender'])) {
  echo "BAH";
} elseif (strtoupper($_REQUEST['gender']) === 'M') {
  echo "SIR";
} elseif (strtoupper($_REQUEST['gender']) === 'F') {
  echo "MADAM";
} else {
  echo "UNKNOWN";
}

这将检查您的条件，而不需要嵌套循环。使用AND操作符

if (isset($_REQUEST['gender']) && $_REQUEST['gender']=='M'){
    echo '<p><b>Good day, Sir!</b></p>';
}
else if (isset($_REQUEST['gender']) && $_REQUEST['gender']=='F'){
    echo '<p><b>Good day, Madam!</b></p>';
}
else if(isset($_REQUEST['gender']) && ( $_REQUEST['gender']!='M'
                                        || $_REQUEST['gender']!='F')){
    echo "INVALID INPUT";
}
else{
  echo '<p class="error">You forgot to select your gender!</p>';  
}

只是为了好玩!(如，这将工作，但相当神秘:-)

echo (array_key_exists("gender",$_REQUEST))?
(strtoupper($_REQUEST['gender'])=="M")?"Good day, Sir!":
((strtoupper($_REQUEST['gender'])=="F")?"Good day, Madam!":
"Gender should be either 'M' or 'F'!"):"You forgot to select your gender!";

作为单行…

echo (array_key_exists("gender",$_REQUEST))?(strtoupper($_REQUEST['gender'])=="M")?"Good day, Sir!":((strtoupper($_REQUEST['gender'])=="F")?"Good day, Madam!":"Gender should be either 'M' or 'F'!"):"You forgot to select your gender!";

看，妈，没有如果!: -)

使用switch语句，您只需要一个if

if (!isset($gender))
  echo "no gender specified";
else
  switch($gender) {
    case "M":
    case "m":
      echo "Good day, Sir"; break;
    case "F":
    case "f":
      echo "Good day, Madam"; break;
    default:
      echo "What gender are you?";
  }