Help me initialize a containers.Map

M = containers.Map('KeyType', 'double')开发者_JS百科

instead of giving me a map that takes keys of type double, it gives me a map that his one key (the string 'KeyType') with value 'double'

-_- What am I doing wrong?

You also have to specify the value type; So you need to write M = containers.Map('KeyType', 'double', 'ValueType', whatever).

Just a note: the reason that the containers.Map() constructor requires both to be specified is that otherwise there would be ambiguity with the containers.Map(keys,values) constructor.

>> f=containers.Map('KeyType','double','ValueType','char')
f = 
  Map with properties:
        Count: 0
      KeyType: double
    ValueType: char
>> f(3)='Hello'
f = 
  Map with properties:
        Count: 1
      KeyType: double
    ValueType: charf=containers.Map('KeyType','char','ValueType','double')

Note that you can also initialize it like:

f=containers.Map({3,4},{'a','foo'})
f = 
  Map with properties:
        Count: 2
      KeyType: double
    ValueType: char