在数组中存储false boolean

I'm trying to store a false boolean into an array, to pass it as value in a PDO prepared statement:

$a = Array('bool' => '0');

if($a['bool'] === '1') {
    $a['bool'] = true;
}
else {
    $a['bool'] = false;
}

print_r($a);

The result is:

Array
(
    [bool] => 
)

I would expect:

Array
(
    [bool] => 0
)

Because if I store a true boolean value, the print_r function prints true as value of 'bool'.

Having the $['bool'] empty doesn't send to my bit field the false value and invalidates my query.

The value is passed with:

$sth->execute( $a );

How can I solve the problem?

For who says "use 1 and 0", well, PDO doesn't accept as boolean values the integers 1 and 0, it needs real booleans.

You may use 1 or 0 for true or false instead. Else, below is another way to do that:

if($a['bool'] === '1') {
    $a['bool'] = intval(true);
} else {
    $a['bool'] = intval(false);
}

use integer 0 or 1 for false or true. It will work like boolean. You should to not use === operator if you use integer as boolean.
you can simple test like this:

if($intVar) {
     //do something it is true
}
else{
 //do something it is false
}

simply asign 0 or 1 in your array like this:

 $a = Array('bool' => 0);

then use it like this:

$sth->execute( $a );

It is not tested but should be work :)

Demo: https://eval.in/98660

 //test for false
  $a = Array('bool' => 0);


    if($a['bool']){
      echo "It is true";
    }
    else {
     echo "It is false 
";
    }

    print_r($a);

    //second test for true

    $a = Array('bool' => 1);




  if($a['bool']){
    echo "It is true";
  }
   else {
     echo "It is false 
";
  }
   print_r($a);

OUTPUT:

It is false 
Array
(
    [bool] => 0
)
It is trueArray
(
    [bool] => 1
)

It does store the boolean value. So when you get the value you should expect a boolean value. If you use var_dump($a) instead of print_r you will see that it is stored perfectly as

array(1) {
  'bool' =>
  bool(false)
}