php if语句的缩写 实例

主要是三目运算符

Basic True / False Declaration

$is_admin = ($user['permissions'] == 'admin' ? true : false);

Conditional Welcome Message

echo 'Welcome '.($user['is_logged_in'] ? $user['first_name'] : 'Guest').'!';

Conditional Items Message

echo 'Your cart contains '.$num_items.' item'.($num_items != 1 ? 's' : '').'.';

Conditional Error Reporting Level

error_reporting($WEBSITE_IS_LIVE ? 0 : E_STRICT);

Conditional Basepath

echo '<base href="http'.($PAGE_IS_SECURE ? 's' : '').'://mydomain.com" />';

Nested PHP Shorthand

echo 'Your score is: '.($score > 10 ? ($age > 10 ? 'Average' : 'Exceptional') : ($age > 10 ? 'Horrible' : 'Average') );

Leap Year Check

$is_leap_year = ((($year % 4) == 0) && ((($year % 100) != 0) || (($year %400) == 0)));

Conditional PHP Redirect

header('Location: '.($valid_login ? '/members/index.php' : 'login.php?errors=1')); exit();

IF ... ELSE

$text = "There ". 
	($total==1 ? "is 1 item" : 
		"are ".($total == 0 ? "no items" : "$total items")
	); 

//Compared to: 

if($total==0) { 
	$text = "There are no items"; 
} 
else if($total==1) { 
	$text = "There is 1 item"; 
} 
else if($total > 0) { 
	$text = "There are $total items"; 
}

if($foo) {  
     $str = 'yes';  
}

//Compared to: 

$foo && $str = 'yes';