SYNOPSIS
	mixed *transpose_array (mixed *arr);

DESCRIPTION
	transpose_array ( ({ ({1,2,3}), ({a,b,c}) }) )
			== ({ ({1,a}), ({2,b)}, ({3,c}) })

	transpose_array() applied to an alist results in an array of
	({ key, data }) pairs, useful if you want to use sort_array()
	or filter_array() on the alist.

EXAMPLE
	sort_array(transpose_array( ({ m_indices(map), m_values(map) }) ),
		   lambda( ({ 'a, 'b }),
			   ({ #'<, ({ #'[, 'a, 0 }),
				   ({ #'[, 'b, 0}) }) )

	The given mapping 'map' is returned as an array of
	({ key,	data })	 pairs, sorted by the keys.

SEE ALSO
	alists(LPC), sort_array(E)
