多维数组判断是否使用基于标志的值

Question

Array ( 
[0] => Array ( [address] => New York [address_flag] => 0 ) 
[1] => Array ( [address] => London [address_flag] => 1)

假设我上面有这个数组，address 1 将永远存在，而 address 2 可以为 null 如何获取 address 2 的值（如果可用）；如何获取我告诉 address 2 是否为空？

我正在这样获取它们的价值

foreach (address() as $value) {

echo $value['address']

}

UPDATE

只有当带有标志 1 的地址不可用时，我才想使用带有标志 0 的地址..如何解决这个问题？任何想法表示赞赏

Answer 1

您可以使用 isset and is_null。例如：-

foreach (address() as $value) {

   echo isset($value['address']) ? $value['address'] : "";
   echo isset($value['address_flag']) ? $value['address_flag'] : "";

}

Answer 2

<?php

function address(){

$a = array(array ( "address" => "New York", "address_flag" => 0 ), 
           array ( "address" => "London",   "address_flag" => 1 ),
           array ( "address" => "Amsterdam","address_flag" => 1),
           array ( "address" => null,       "address_flag" => null));

return $a;
}

$address = '';
$grouped_by_zero = array();
$grouped_by_one = array();
$array = address();

for ($i=0, $max = count($array); $i < $max; $i++ ){
    foreach($array[$i] as $key => $value) {
      if ($key == "address") {
         $address = $value;
      }     
      if ($key == "address_flag"){
          if ( $value === 0 ){
            array_push($grouped_by_zero,$address);
          } else if ($value === 1) {
              array_push($grouped_by_one,$address);
          }
      }// end outer if      
    }// end foreach
}// end for

foreach($grouped_by_zero as $item){
    echo $item . "\n";
}
echo "\n";
foreach($grouped_by_one as $item){
    echo $item . "\n";
}
//output:

New York

London
Amsterdam

现场演示：http://3v4l.org/3utBH

通过使用恒等运算符===，排除空值；只接受等于 0 或 1 的值。

多维数组判断是否使用基于标志的值

multidimensional array tell if a use a value based on flag

php

arrays

multidimensional-array