pandas

Working with large csv files would be a real pain for me if it weren't for pandas. I have used pandas in college, in hobby projects and professionally to manipulate data ranging from a few hundred entries to hundreds of thousands of entries, and the performance has always been very good. Pandas has everything you'd ever want for manipulating large amounts of data: speed, efficiency, ease of use, ability to deal with missing values, and much more.

I used pandas to transform ohlcv data using the yfinace library and modifying it to calculate moving average convergence divergence, simple moving averages and perform technical analysis on stock market data. very efficient and easy to transform data that never had to look beyond it.

I mostly use it to work with tabular data and use it to convert data from one form to the other in terms of the format and the structure of the data. Financial data analysis like stock price is a good use case where Pandas really shines.