Python, Java or R?

Python is a very useful tool. I would take some time to study up on it.

R and Java are taught within the industry, though R is more structured towards data. Industry these days are dedicating their automation tools in Python due to their versatility.

Python is the most useful these days. Pandas was developed at AQR!

Python for sure

Really depends what your role is going is/going to be.

Excel/Valuation: VBA --> Python with numpy/pandas/xlwings is great.

The people I know who use R are all using it for extremely intricate statistical analysis (quants/nuclear engineers hired to the SS/BS)

python 100% pandas/scitklit learn/matplot lib

only things you need to know

Not related. But if you have the time learn C from the basics for 6 months and then C++ for 3 months. If you become proficient in these trust me you can easily pickup most languages.

I'd learn Java first because it's a lot stricter and would, theoretically, make you more efficient when coding python. Python is known to be a bit relaxed with its' syntax roles and leaves more room for mistakes

To continue this thread, what is the best website to learn Python? Website for beginners? Then financial/trading applications?

Python would probably be the best investment up front. Easy to learn/ read, tons of packages and growing use in the industry. Unlike R you can write full production quality code. My friend who works at AQR says this is 100% the best language to learn as a first language.

R is most useful for advanced statistical analysis - often times when pHD researchers release a paper with a new methodology they release an R package to accompany it . Often time I hear of people using R in the research stage and python for implementation

Java definitely is falling out - also fairly close to Python, so if you learned python first it would be pretty quick to switch over if you had to. Some structural difference, syntax and static vs dynamic typing. The one case where this might be useful is if your company doesn't let you use open source languages - but the industry seems to be warming up.

Finally, strangely enough excel's VBA is pretty useful at times. Horrible language to build stuff in and debug but it comes with the whole excel interface that people are super comfortable with in finance. Working on sell side trading, pretty much every desk had some sort of VBA system running.

Python and SQL