矩阵和数组

Question

I have a problem I can not solve this task at all. can you help me.

We have a multivariate array that describes something like an Excel table or matrix, ect. the first index represents the row and the second column. The rows can have a different number of elements (columns). Count the amounts in the columns and select the highest.

$a = [[1, 3, 4], [2, 5], [2 => 3, 5 => 8], [1, 1, 5 => 1]];

Answer 1

Here's some code that does what you asked:

$a = [[1, 3, 4], [2, 5], [2 => 3, 5 => 8], [1, 1, 5 => 1]];

$columnValues = [];
$lastColumn = 0;
foreach($a as $row){
    foreach($row as $column => $value){
        if($column > $lastColumn)
            $lastColumn = $column;

        if(isset($columnValues[$column]))
            $columnValues[$column] += $value;
        else 
            $columnValues[$column] = $value;
    }
}

//if you want to include empty columns too:
for($column = 0; $column <= $lastColumn; $column++){
    if(!isset($columnValues[$column]))
        $columnValues[$column] = 0;
}

//sorting the column values by index:
ksort($columnValues);

$highestValue =  max($columnValues);
$highestValueColumns = array_keys($array, max($array)); //contains all columns that have the same highest value. If there's only one column with the highest value, you can access it with $highestValueColumns[0];