What does the c underscore expression `c_` do exactly?

Question

It seems to be some kind of horizontal concatenation, but I could not find any documentation online. Here a minimal working example:

In [1]: from numpy impo         


        

Answer 1

Actually it is not a function, it is an object of class CClass.

it is "not a function, so takes no parameters

Above is what the official document said. you can check this question for details.

numpy.r_ is not a function. What is it?