ruby在php中有类似的多维数组吗？

Question

like in php:

$input = [
      'a' => 'A',
      'b' => 'B',
      'cdef' => [
             'c' => 'C',
             'd' => 'D',
             'ef' => [
                  'e' => 'E',
                  'f' => 'F'
             ]
      ]
]

maybe use Hash? never used ruby before :)

When I worte code:

input = Hash.new
input['a'] = 'A'
input['b'] = 'B'
input['cdef']['c'] = 'C'
input['cdef']['d'] = 'D'
input['cdef']['ef']['e'] = 'E'
input['cdef']['ef']['f'] = 'F'

error at

  input['cdef']['c'] = 'C'

message :

[]=' for nil:NilClass

Answer 1

Although the answer by @davidhu2000 is more or less correct, I would go with more robust solution: using default_proc in the constructor. The dup.clear magic is to recursively pass the default_proc through to deeply nested elements:

input = Hash.new { |h, k| h[k] = h.dup.clear }
input['a'] = 'A' 
input['b'] = 'B' 
input['cdef']['c'] = 'C' 
input['cdef']['d'] = 'D' 
input['cdef']['ef']['e'] = 'E' 
input['cdef']['ef']['f'] = 'F' 

input

That way one does not need ugly redundant assignments:

input['cdef'] = {}
input['cdef']['ef'] = {} 

Ninja assignment:

input = Hash.new { |h, k| h[k] = h.dup.clear }
input['a1']['a2']['a3']['a4']['a5'] = 42
input
#⇒ {"a1" => {"a2" => {"a3" => {"a4" => {"a5" => 42}}}}}