Ruby相当于Java的Collections.unmodifiableList和Collections.unmodifiableMap

Question

Java的Collections.unmodifiableList和Collections.unmodifiableMap的Ruby标准API中是否有等价物？

Answer 1

Use freeze API:

Prevents further modifications to obj. A RuntimeError will be raised if modification is attempted. There is no way to unfreeze a frozen object. See also Object#frozen?.

This method returns self.

 a = [ "a", "b", "c" ] a.freeze a << "z" 

produces:

 prog.rb:3:in `<<': can't modify frozen array (RuntimeError) from prog.rb:3 

You can also use the hamster gem for other immutable data structures.

Answer 2

If you want to create, for example, unmodifiable (immutable) list:

a = [ "a", "b", "c" ]
a.freeze