[
0=>52,
1=>45,
2=>58
][
38=>47,
78=>68
45=>85,
]
$a = ['0' => '52',
'1' => '45',
'2' => '58'];
$b = ['38' => '47',
'78' => '68',
'45' => '85'];
foreach ($b as $key => $value) {
if(in_array($key, $a)){
unset($b[$key]);
}
}
print_r($b);