Getting started with NumPy

In Chapter 2, Python Programming Specificities, we stated that Python is a dynamically typed language. This means that the interpreter automatically detects the type of a variable at runtime, and this type can even change throughout the program. For example, you can do something like this in Python:

$ python
>>> x = 1
>>> type(x)
<class 'int'>
>>> x = "hello"
>>> type(x)
<class 'str'>

The interpreter was able to determine the type of x at each assignation.

Under the hood, the standard implementation of Python, CPython, is written in C. The C language is a compiled and statically typed language. This means that the nature of the variables is fixed at compile time, and they can't change during execution. Thus, in the Python implementation, a variable doesn't only consist in its value: it's actually a structure containing information about the variable, including...