How does Set::nest in Cakephp 2 works? - cakephp

Question

Due to the lack of proper documentation I have difficulties
to understand "Set::nest" CakePhp function.
I would appreciate if somebody can explain generally
and with my example how to use it properly.
Let's say I have this tree:
array(
(0) => array(
'Category' => array('name' => 'Cat 1'),
'Course' => array(
'name' => 'Course 1'
),
'Day' => array('date' => '2012-01-01')
),
(1) => array(
'Category' => array('name' => 'Cat 1'),
'Course' => array(
'name' => 'Course 1'
),
'Day' => array('date' => '2012-01-02')
),
(2) => array(
'Category' => array('name' => 'Cat 1'),
'Course' => array(
'name' => 'Course 3'
),
'Day' => array('date' => '2012-01-06')
),
(3) => array(
'Category' => array('name' => 'Cat 2'),
'Course' => array(
'name' => 'Course 2'
),
'Day' => array('date' => '2012-01-02')
),
)
to be transformed to:
array(
'Cat 1' => array(
'Course' => array(
'name' => 'Course 1'
),
'Day' => array(
array('date' => '2012-01-01'),
array('date' => '2012-01-02')
),
'Course' => array(
'name' => 'Course 3'
),
'Day' => array(
array('date' => '2012-01-06')
),
),
'Cat 2' => array(
'Courses' => array(
'name' => 'Course 2'
),
'Day' => array(
array('date' => '2012-01-03')
)
),
)
As you can see it's kind of a double nesting because "Category" can have multiple "Course" rows and "Course" can have multiple "Day".
I could just loop through it and do it manually.
So the fist question is: can I transform this with Set::nest at all
and if yes how?

Answer 1

What you are asking for is impossible. Your array is not valid. You need to change your format to have each category as a nested array 'cat' => array(array('course 1' => ...), array('course 2' => ...))
print_r(array(
'Cat 1' => array(
'Course' => array(
'name' => 'Course 1'
),
'Day' => array(
array('date' => '2012-01-01'),
array('date' => '2012-01-02')
),
'Course' => array(
'name' => 'Course 3'
),
'Day' => array(
array('date' => '2012-01-06')
),
),
'Cat 2' => array(
'Courses' => array(
'name' => 'Course 2'
),
'Day' => array(
array('date' => '2012-01-03')
)
),
));
Output:
Array
(
[Cat 1] => Array
(
[Course] => Array
(
[name] => Course 3
)
[Day] => Array
(
[0] => Array
(
[date] => 2012-01-06
)
)
)
[Cat 2] => Array
(
[Courses] => Array
(
[name] => Course 2
)
[Day] => Array
(
[0] => Array
(
[date] => 2012-01-03
)
)
)
)