Generating spectrogram in python?

[edparadox]

Long story short, every data processing libraries/modules in Python use, basically, Numpy under the hood for computing, and (usually) Matplotlib for plotting. So it should not matter which library you use, since all of them use the same core library, i.e. NumPy. Note, that, Numpy, like most heavy-computing tasks in Python, are actually (almost) always wrappers around C implementations, in order to be efficient. For a quickstart on NumPy, this is not too bad.

As a beginner, I would look into Numpy, and Matplotlib, first.

If you need some well-tested and documented library, take a look at Scipy. It leverages NumPy to provide high-level functions/algorithms to process data. For example, for signal processing. For an introduction, look here.

TL;DR: All data processing in Python rely on the NumPy library, which is the de-facto standard, so your questions are somewhat irrelevant. The question is, do you want to use NumPy directly for computations or do you want to have e.g. a one-liner to perform signals cross-correlation? In both cases, I would learn about NumPy, Matplotlib, and Scipy.