Php judges the number of empty one-dimensional arrays in two-dimensional arrays without loops as far as possible.

I would like to ask php how to determine whether each one-dimensional array in a two-dimensional array is empty without using for and other loops, and count out the number of empty arrays, and find out the relevant functions in the system function. 

 $a = [
        [],
        [],
        [],
        [],
        []
    ];

$b = [
    ["a" => 1],
    [],
    [],
    ["b" => 2],
    []
];

for example, how do the above two arrays give elegant answers without loops or loops?

Php
Apr.07,2021 
$b = [
    ['a' => 1],
    [],
    [],
    ['b' => 2],
    []
];

// 
$tmp = array_filter($b);

echo '
';
var_dump(array_diff_key($b, $tmp));


 result: 


array(3) {
  [1]=> array(0) { }
  [2]=> array(0) { }
  [4]=> array(0) { }
}



 these functions must still be loops inside 




 if you only count the number of empty spaces, the following code should be able to 


$a = [
        ['a' => 1],
        [],
        [],
        [],
        []
    ];

$b = array_filter($a);

$nullnum = count($a)-count($b);

echo $nullnum;


 
$b = [
    ['a' => 1],
    [],
    [],
    ['b' => 2],
    []
];
array_walk($b,function ($v) use(&$num){empty($v) ? $num += 1 : '';});
var_dump($num);
 
 
 json_encode? Then query the number of occurrences of the string  [] ?

Previous: To introduce the use of vue.js CDN (non-vue-cli), can you use these guard functions of beforeRouteLeave?

Next: A small question about v-for on a < template >

css mysql arrays josn react html typescript webpack npm sass R objective-c .net sql-server jquery python-3.x angularjs django angular excel regex iphone ajax linux xml pandas vba spring database wordpress string wpf xcode windows bash postgresql oracle multithreading eclipse list firebase algorithm macos forms image scala visual-studio azure bootstrap spring-boot react-native python-2.7 docker performance function winforms matlab powershell apache dataframe api sqlite numpy rest shell selenium flutter dart maven loops qt swing android-studio csv express file class tensorflow sorting codeigniter perl
MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1b417b2-2b2dc.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1b417b2-2b2dc.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
Need Help?