How to use PHP to convert a matrix into a two-dimensional array

In PHP, a matrix is ​​a rectangular grid data structure composed of rows and columns. In practical applications, it is often necessary to convert matrices into two-dimensional arrays for processing. This article will introduce how to use PHP to convert a matrix into a two-dimensional array.

First, let us look at a simple matrix example:

$matrix = array(
    array(1, 2, 3),
    array(4, 5, 6),
    array(7, 8, 9)
);

The above matrix consists of 3 rows and 3 columns, and each element corresponds to an integer. We convert it into a two-dimensional array, that is, add each element of the matrix to a new Array, as follows:

$array = array();
foreach ($matrix as $row) {
    foreach ($row as $cell) {
        $array[] = $cell;
    }
}

The two-dimensional array obtained at this time is: [1, 2, 3, 4, 5, 6, 7, 8, 9], each element is added to the array in order in a row-major manner.

However, the complexity of this method is O(n²) and is less efficient when processing large matrix data. Below we will introduce a method based on array pointers that can convert a matrix into a two-dimensional array with O(n) complexity.

First, you need to use the reset() function to position the pointer to the first element of the matrix.

reset($matrix);

Next, you need to use the current() function to get the element pointed to by the current pointer, then add it to the new array, and use next() Function moves the pointer to the next element.

$array = array();
while ($row = current($matrix)) {
    while ($cell = current($row)) {
        $array[] = $cell;
        next($row);
    }
    next($matrix);
    reset($row);
}

The results obtained at this time are the same as before, but because loop nesting is not used, the efficiency is higher, especially when processing large-scale matrix data.

Finally, we provide a complete sample code for reference.

$matrix = array(
    array(1, 2, 3),
    array(4, 5, 6),
    array(7, 8, 9)
);

reset($matrix);
$array = array();
while ($row = current($matrix)) {
    while ($cell = current($row)) {
        $array[] = $cell;
        next($row);
    }
    next($matrix);
    reset($row);
}

print_r($array);

The above are two methods of converting a PHP matrix into a two-dimensional array. I believe it will be helpful to readers who deal with matrix data.

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