Filter a 2d array to keep rows which have a specified column value

I have an array like this:

[0] => Array(
    [student_id] => 6
    [gender] => 1
    [student_name] => name1
)

[1] => Array(
    [student_id] => 26
    [gender] => 2
    [student_name] => name2
)

[2] => Array(
    [student_id] => 75
    [gender] => 2
    [student_name] => name3
)

[3] => Array(
    [student_id] => 1
    [gender] => 1
    [student_name] => name4
)

[4] => Array(
    [student_id] => 10
    [gender] => 1
    [student_name] => name5
)

I would like to list the student names or array keys where gender is 2.

What is the most efficient way to achieve this?

Avoiding foreach should be better.

You could use array_filter to filter the array.

$students = array_filter($students, function($var) {
    return $var['gender'] === 2;
});

And if you want to collect the names as an array, there is array_map:

$names = array_map(function($var) {
    return $var['student_name'];
}, $students);