For efficiency, with an object-oriented paradigm (and even some functional
bits): C++14. On the negative side, the language is not safe (you cannot have
both efficiency and safety) and is complicated, hard to master. The standard
template library does not contain much but many excellent libraries exist
(search the boost library first).
When efficiency matters less than productivity: Python 3. It is, nowadays,
one of the most popular language (what means many libraries are available).
It is object-oriented and safe. Ruby is similar, has its fans, but is less
popular, hence less libraries.
To process text inputs: AWK. You can do so many things by writing, in a
matter of seconds/minutes, a few lines of AWK.
I would argue that those three languages cover all needs (notice that C++ is
a superset of C). Some would argue that, between C++ and Python, there is
room for a language like Java. I personally do not think so: either choose
efficiency (C++) or productivity (Python).
