Please keep in mind: this is just a JavaScript thing and has nothing to do with Angular JS. So don't be confused about the magical '$' sign ;)
The main problem is that this is an hierarchical structure.
console.log($scope.life.meaning); // <-- Nope! This is undefined.
=> a.b.c
This is undefined because "$scope.life" is not existing but the term above want to solve "meaning".
A solution should be
var the_string = 'lifeMeaning';
$scope[the_string] = 42;
console.log($scope.lifeMeaning);
console.log($scope['lifeMeaning']);
or with a little more efford.
var the_string_level_one = 'life';
var the_string_level_two = the_string_level_one + '.meaning';
$scope[the_string_level_two ] = 42;
console.log($scope.life.meaning);
console.log($scope['the_string_level_two ']);
Since you can access a structural objecte with
var a = {};
a.b = "ab";
console.log(a.b === a['b']);
There are several good tutorials about this which guide you well through the fun with JavaScript.
There is something about the
$scope.$apply();
do...somthing...bla...bla
Go and search the web for 'angular $apply' and you will find information about the $apply function. And you should use is wisely more this way (if you are not alreay with a $apply phase).
$scope.$apply(function (){
do...somthing...bla...bla
})