检查其他数组中的关联数组？

I have two array $A,$B

$B = Array
(
    [0] => Array
        (
            [id_participant] => 94
            [full_name] => soeng makara
        )

    [1] => Array
        (
            [id_participant] => 95
            [full_name] => sok sao
        )

)

$A = Array
(
    [0] => Array
        (
            [id_participant] => 95
            [full_name] => sok sao
        )
)

Anyone could help me How can I check array $A in array $B in that case.

Simply:

if (in_array($A[0], $B))
{
  // in array
}

You want to know if the item in $a is in $b?

function checkIfInArray($a, $b)    
{
    foreach($b as $i)
        foreach($a as $x)
            if($x['id_participant'] == $i['id_participant']) return true; //Match found
    return false; //No Match was found
}