But you can have both. In Scala I can write prototypes just as rapidly as Python, but I can run them with close-to-native performance. I can even explore interactively in a REPL but backed by the power of my company&#x27;s big computer cluster, using spark-shell. The profiling capabilities are excellent, but when I spot a bottleneck I can solve it in the language directly, without needing the awkwardness of cython or of converting to&#x2F;from numpy formats.<p>(And while I personally love Scala, there&#x27;s nothing magic about it in this regard. There&#x27;s no reason a language can&#x27;t offer Python-like expressiveness and Java-like performance, and many modern languages do)