FrederikNS

Most semi-primitive types in python is immutable, yes (int, float, char, str, and DateTime), but all of the collections are mutable (List, Dict, Set).

I'm sure there are immutable versions of those same data structures hidden somewhere in the standard library, but I haven't looked.

I did stumble upon pyrsistent (https://github.com/tobgu/pyrsistent) a while ago which does provide proper immutable (and persistent) data structures for python.

Scala enables you to keep most of the Java ecosystem (API, docs, cross-platform, and swing is even nicer in scala), and you can do `people.map { p => (p.name, p.address) }`, granted that the IDEs have to get a plugin installed before they are as helpful, but both Eclipse and IntelliJ has awesome scala plugins.