I do a little work in machine learning (as an undergrad). Deep learning specifically is dominated by Python and C++ (Python for the interface, C++/CUDA for the implementation). Theano's interface is in Python. Caffe has C++, Python, and Matlab interfaces (Python and C++ being the most popular in my experience). Tensorflow has C++ and Python interfaces. ipython notebooks started with Python. The odd one out is Torch; its interface is in Lua.
Machine learning also, at least from my academic view, seems to be dominated by C++/Matlab/Java/Python (and things seem to be moving to Python).
But more broadly, you'll have to learn dozens of languages as a programmer anyways. I wouldn't get too caught up in Python vs. other things.
Machine learning also, at least from my academic view, seems to be dominated by C++/Matlab/Java/Python (and things seem to be moving to Python).
But more broadly, you'll have to learn dozens of languages as a programmer anyways. I wouldn't get too caught up in Python vs. other things.