Transpose 2d array, join second level with commas, and join first level with pipes

Question

I have the following two-dimensional array:

01 03 02 15
05 04 06 10
07 09 08 11
12 14 13 16

I want to convert columns to rows then reduce the matrix to a string like the following:

01,05,07,12|03,04,09,14|02,06,08,13|15,10,11,16

Answer 1

I'm assuming that you have this array:

$array = array (
  array ('01','03','02','15'),
  array ('05','04','06','10'),
  array ('07','09','08','11'),
  array ('12','14','13','16')
);

In which case, you can do this:

$tmpArr = array();
foreach ($array as $sub) {
  $tmpArr[] = implode(',', $sub);
}
$result = implode('|', $tmpArr);
echo $result;

See it working

Answer 2

$input = array(
    array('01', '02', '03', '04'),
    array('11', '12', '13', '14'),
    array('21', '22', '23', '24'),
    array('31', '32', '33', '34'),
);
$newArray = array();
foreach($input as $rowIndex => $row) {
    foreach($row as $key => $val) {
        if(!$newArray[$key]) {
            $newArray[$key] = array();
        }
        $newArray[$key][$rowIndex] = $val;
    }
}
$strRows = array();
foreach($newArray as $key => $row) {
    $strRows[$key] = join(',', $row);
}
$output = join('|', $strRows);

Answer 3

The most elegant script for this "transpose and double-implode" task is to call array_map() with a spread operator on the input array, then join the columns with commas, the join the joined strings with pipes.

Code: (Demo)

var_export(
    implode(
        '|',
        array_map(
            fn() => implode(',', func_get_args()),
            ...$input
        )
    )
);

Or collect all of the column data in the function signature. (Demo)

var_export(
    implode(
        '|',
        array_map(
            fn(...$column) => implode(',', $column),
            ...$input
        )
    )
);

For similar questions that do not require a single string of output, but prefer an array of delimited strings, simply remove the outer implode() call. Namely:

• (2015) assoc arrays to two different arrays and join them
• (2017) How to transpose and implode subarray data within a multidimensional array to create a flat output array?
• (2018) php concat array values into new array php
• (2019) Transpose multidimensional array and join values with commas

Answer 4

Given your array as $myArray, like this:

$newArray = array();
foreach ($myArray as $row) {
    $rowValue = implode(',', $row);
    $newArray[] = $rowValue;
}
$finalString = implode('|', $newArray);

Answer 5

Looking at the solutions proposed so far, only one actually generates the correct output requested by the OP.

So, stealing unashamedly from salathe's neat conversion, but with a transpose to provide the correct result:

$input = array ( 
    array ('01','03','02','15'), 
    array ('05','04','06','10'), 
    array ('07','09','08','11'), 
    array ('12','14','13','16'), 
); 

function transpose($array) {
    array_unshift($array, null);
    return call_user_func_array('array_map', $array);
}

$transposed = transpose($input);

echo implode('|', array_map('implode', $transposed, array_fill(0, count($transposed), ',')));