Adding numbers in a multidimensional array

Question

Is there a faster way to add all the numbers in each segment of the multidimensional array rather than just doing it all manually? I was told before that a foreach loop could be used but I've hit a brick wall.

I'm trying to make it so it shows the total number of course enrollments in each campus and then the total number of students taking each course.

I feel like the answer is staring me in the face but I'm unsure.

<?

$campus = array();

$campus[1]['course1'] = 5;   // <---- Number enrolled
$campus[1]['course2'] = 15;
$campus[1]['course3'] = 22;
$campus[1]['course4'] = 21;
$campus[1]['course5'] = 12;
$campus[1]['course6'] = 25;
$campus[1]['course7'] = 16;
$campus[1]['course8'] = 11;
$campus[1]['course9'] = 17;
$campus[1]['course10'] = 23;

$campus[2]['course1'] = 11;
$campus[2]['course2'] = 23;
$campus[2]['course3'] = 51;
$campus[2]['course4'] = 25;
$campus[2]['course5'] = 32;
$campus[2]['course6'] = 35;
$campus[2]['course7'] = 32;
$campus[2]['course8'] = 52;
$campus[2]['course9'] = 25;
$campus[2]['course10'] = 21;

$campus[3]['course1'] = 2;
$campus[3]['course2'] = 12;
$campus[3]['course3'] = 32;
$campus[3]['course4'] = 32;
$campus[3]['course5'] = 25;
$campus[3]['course6'] = 26;
$campus[3]['course7'] = 29;
$campus[3]['course8'] = 12;
$campus[3]['course9'] = 15;
$campus[3]['course10'] = 11;

echo "<pre>";
print_r($campus);
echo "<br/>";

foreach($campus as $key=>$value)
{

}

foreach($campus as $key => $values) { echo $key, ' -> ', array_sum($values); } — Mark Baker
– Mark Baker, Commented Oct 6, 2014 at 15:52
For the total number of students taking each course, you can use array_column() with array_sum() (if you're using PHP >= 5.5) otherwise use an array_map() instead of array_column() — Mark Baker
– Mark Baker, Commented Oct 6, 2014 at 15:53
I do not, how would one use it for this? I took a look at it and I can kinda see what it's doing. — Knifehead
– Knifehead, Commented Oct 6, 2014 at 15:53

Barmar · Accepted Answer · 2014-10-06 15:53:21Z

1

Use array_sum() to add the numbers in an array, and use array_map() to apply it to each element of the $campus array.

$total_by_campus = array_map('array_sum', $campus);

answered Oct 6, 2014 at 15:53

Barmar

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2 Comments

Knifehead Over a year ago

When I tried to do this, I ended up getting this error - Notice: Array to string conversion in C:\xampp\htdocs\Work\arrays_courses.php on line 43

Barmar Over a year ago

What's on line 43? You can't echo an array, you have to use var_dump() to see what's in it.

blue112 · Accepted Answer · 2014-10-06 15:51:34Z

0

$courses = array();
foreach($campus as $key=>$value)
{
    foreach($value as $course=>$num)
        $courses[$course] += $num;
}
var_dump($courses);

Should do it.

answered Oct 6, 2014 at 15:51

blue112

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Comments

helllomatt · Accepted Answer · 2014-10-06 15:53:01Z

0

You can use PHP's array_sum() function that will add up the values of the array you give it.

<?php

$sum = array_sum($campus[1]);
echo $sum;

answered Oct 6, 2014 at 15:53

helllomatt

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Comments

Yash Sodha · Accepted Answer · 2014-10-06 15:58:30Z

0

$totcount = 0;
$count  = array();
foreach($campus as $key=>$value)
{
    foreach($value as $value1 => $value2)
    {
        $count[$value1]+=$value2;
        $totcount++;
    }
}

print_r($count);
echo "<br><br><br>". $totcount;

answered Oct 6, 2014 at 15:58

Yash Sodha

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Comments

Jacky Lormoz · Accepted Answer · 2014-10-29 16:58:05Z

take a look:

$campus = array
(
    '1' => array
    (
        'course1'  => 5,
        'course2'  => 15,
        'course3'  => 22,
        'course4'  => 21,
        'course5'  => 12,
        'course6'  => 25,
        'course7'  => 16,
        'course8'  => 11,
        'course9'  => 17,
        'course10' => 23,
    ),
    '2' => array
    (
        'course1'  => 11,
        'course2'  => 23,
        'course3'  => 51,
        'course4'  => 25,
        'course5'  => 32,
        'course6'  => 35,
        'course7'  => 32,
        'course8'  => 52,
        'course9'  => 25,
        'course10' => 21,
    ),
    '3' => array
    (
        'course1'  => 2,
        'course2'  => 12,
        'course3'  => 32,
        'course4'  => 32,
        'course5'  => 25,
        'course6'  => 26,
        'course7'  => 29,
        'course8'  => 12,
        'course9'  => 15,
        'course10' => 11,
    ),
);

foreach ($campus as $key0 => $value0)
{
    // $key0 == (1, 2, 3)
    // $value0 == array(course1 => 5, course2 => 15, course3 => 22, ...)
    foreach ($value0 as $key1 => $value1)
    {
        // $key1 == (course1, course2, course3, ...)
        // $value1 == (5, 15, 22, ...)
    }
}

Sorry, but you post a question: "How to check an array's contents to see if they have any numbers?"

<?php

$cowboyfile = "COWBOY.TXT";

$data = array();
$data[] = "Colt Peacemaker, 12.20";
$data[] = "Holster, 2.00";
$data[] = "Levi Strauss Jeans, 1.35";
$data[] = "Saddle, 40.00";
$data[] = "Stetson, 10.00";
// Writing in the File
file_put_contents($cowboyfile, implode("\r\n", $data));

// Displaying all items above $10
$items = file($cowboyfile);
$item_filtred = array();
for ($i = 0; $i < count($items); $i++)
{
    $item = $items[$i];
    $item_price = substr($items[$i], strpos($item, ',') + 1);
    if ($item_price >= 10)
    {
        $item_filtred[] = $item;
    }
}
print_r($item_filtred);

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Adding numbers in a multidimensional array

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