What does ^ mean?

Answer 1

Inversion of expression. I.e. ^digits = all but digits

Answer 2

its a metasymbol that defines the start of the row in string variable, in opposition to $ (the end of the row). IMHO to multiply 2*2*2 it is possible to use 2**3 syntax

Answer 3

On the string it means that it has to start with it (i.e..: r"^h" it must start with h).

On a class it inverts it (i.e.: r"[^A-Z]" it must not have capital letters).

Remember that [ ] means it's a class.

Answer 4

power....suppose 2^3 means 2*2*2