Getting the values of a multidimensional array where key value is in another array

Question

I have an array of courses:

 Array
        (
           [0] => BIOL-1108
           [1] => BIOL-1308
           [2] => BIOL-2401
           [3] => BIOL-2402
       )

And a multidimensional array of completed courses that looks like this:

Array
(
    [course] => Array
        (
            [0] => Array
                (
                    [course] => BIOL-2401
                    [title] => BIOL-2401 - Human Anatomy & Physiology I
                    [grade] => A
                )

            [1] => Array
                (
                    [course] => HIST-1301
                    [title] => HIST-1301 - History of the U.S. I
                    [grade] => B
                )

            [2] => Array
                (
                    [course] => MATH-0303
                    [title] => MATH-0303 - Intermediate Algebra
                    [grade] => F
                )
             [3] => Array
                (
                    [course] => BIOL-1108
                    [title] => BIOL-1108 - Life Science I Lab
                    [grade] => B
                )

            [4] => Array
                (
                    [course] => BIOL-1308
                    [title] => BIOL-1308 - Life Science I
                    [grade] => C
                )

       )
)

I want to echo only the course, title and grade if it exists in the first array. I think I am needing a foreach loop, but I'm stuck.

Just to confirm: your expected output here would be 2401 and 1308? — Jaquarh
– Jaquarh, Commented Nov 23, 2020 at 18:28
yes, those three. I'll then have the course array check against 7 other arrays with similar coursa data (math, fine arts etc.) — trf
– trf, Commented Nov 23, 2020 at 19:42

bigtunacan · Accepted Answer · 2020-11-23 18:51:20Z

1

You are on the right track in that you need to loop over your multi-dimensional array values and then see if the courses are in your course array. This can be done using a foreach in conjunction with the in_array function.

<?php
        
$courses = array('BIOL-1108', 'BIOL-1308', 'BIOL-2401','BIOL-2402');

$completed_courses = array(
    'course' => array(
                array(
                    'course' => 'BIOL-2401',
                    'title' => 'BIOL-2401 - Human Anatomy & Physiology I',
                    'grade' => 'A'
                ),
                array(
                    'course' => 'HIST-1301',
                    'title' => 'HIST-1301 - History of the U.S. I',
                    'grade' => 'B'
                ),
                array
                (
                    'course' => 'MATH-0303',
                    'title' => 'MATH-0303 - Intermediate Algebra',
                    'grade' => 'F'
                ),
                array
                (
                    'course' => 'BIOL-1108',
                    'title' => 'BIOL-1108 - Life Science I Lab',
                    'grade' => 'B'
                ),
                array
                (
                    'course' => 'BIOL-1308',
                    'title' => 'BIOL-1308 - Life Science I',
                    'grade' => 'C'
                )

       )

    );

  

foreach( $completed_courses['course'] as $curr ){
    if(in_array($curr['course'], $courses)) {
        echo 'COURSE : ' . $curr['course'] . PHP_EOL;
        echo 'TITLE : ' .  $curr['title'] . PHP_EOL;
        echo 'GRADE : ' .  $curr['grade'] . PHP_EOL;
    }
}

edited Nov 23, 2020 at 18:51

answered Nov 23, 2020 at 18:45

bigtunacan

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2 Comments

trf Over a year ago

This is the one that worked best for me, and was easiest to adapt. Much appreciated!

bigtunacan Over a year ago

Glad I could help

pavel · Accepted Answer · 2020-11-23 18:45:58Z

1

You're probalby looking for array_flip function, than it's quite simply.

<?php

$courses = [
    'BIOL-1108',
    'BIOL-1308'
];

$completed = [
    'course' => [
        [
            'course' => 'BIOL-1108',
            'title' => 'title',
            'grade' => 'C'
        ],
        [
            'course' => 'BIOL-1308',
            'title' => 'title',
            'grade' => 'C'
        ],
        [
            'course' => 'BIOL-1408',
            'title' => 'title',
            'grade' => 'C'
        ]
    ]
];


$courses = array_flip($courses);

foreach ($completed['course'] as $row) {
    if (!isset($courses[$row['course']])) {
        echo $row['course'] . '<BR>'; // returns BIOL-1408 in my example
    }
}

answered Nov 23, 2020 at 18:45

pavel

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2 Comments

trf Over a year ago

I'd need it to pull 2 of the three and not BIOL-1408 in this example. would isset instead of !isset be right instead

pavel Over a year ago

@trf: sorry, isset do the job :-)

Jaquarh · Accepted Answer · 2020-11-23 18:45:58Z

1

You can loop through your array (assuming variable names) and use the in_array to check if the course title exists.

foreach($user['course'] as $course):
    if(in_array($course['title'], $completedCourses)):
        printf('Title: %s, Grade: %s', $course['title'], $course['grade']);
    endif;
endforeach;

answered Nov 23, 2020 at 18:45

Jaquarh

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1 Comment

trf Over a year ago

Well apparently I have 3 answers that work. Thanks to all three of you. I've accepted the first answer even though all three technically do the job. but all get upvoted. I look forward to any comments that come in so I can learn a bit more.

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