ArrayTable

use Derafu\Array\ArrayTable;

Columns into Rows

columnsToRows($array, $keys = null) transposes column groups into rows. Columns are read at zero-based positions.

ArrayTable::columnsToRows(['name' => ['Alice', 'Bob'], 'age' => [30]]);
// [
//     ['name' => 'Alice', 'age' => 30],
//     ['name' => 'Bob', 'age' => null],
// ]

ArrayTable::columnsToRows(['name' => ['Alice']], ['name', 'email']);
// [['name' => 'Alice', 'email' => null]]

The longest selected column determines the number of rows. Missing positions and selected columns that do not exist supply null. If no selected column exists, the result is empty. With no $keys, every column is selected.

Pairs into a Map

pairsToMap($table) requires each row to be an array with exactly two columns. The first column becomes the key and the second its value. Column order determines their role, including for rows with named columns.

ArrayTable::pairsToMap([['name', 'Alice'], ['age', 30]]);
// ['name' => 'Alice', 'age' => 30]

Keys may be scalar or null. Integers stay integers; other accepted keys are converted to strings before PHP applies its array-key rules. For example, null becomes '', true becomes '1' (stored as integer 1) and 2.7 becomes '2.7'.

Later duplicate keys replace earlier values. Invalid rows, or keys that are arrays, objects or resources, throw a translatable Derafu\Array\Exception\ArrayException, which extends InvalidArgumentException. Despite its name, this transformation can produce integer keys; use ValueType::map() separately if string-only keys are required.

Row Keys into a Column

withKeyColumn($data, $idField) adds each row’s array key as a column:

ArrayTable::withKeyColumn(['u1' => ['name' => 'Alice'], 'u2' => ['name' => 'Bob']], 'id');
// ['u1' => ['id' => 'u1', 'name' => 'Alice'], 'u2' => ['id' => 'u2', 'name' => 'Bob']]

Outer keys are preserved. A row that already has the named column keeps its own value: the operation supplies a default identifier rather than overwriting it. All three transformations return new arrays.