Why is “import *” bad?

Question

It is recommended to not to use import * in Python.

Can anyone please share the reason for that, so that I can avoid it doing next time?

Answer 1

These are all good answers. I'm going to add that when teaching new people to code in Python, dealing with import * is very difficult. Even if you or they didn't write the code, it's still a stumbling block.

I teach children (about 8 years old) to program in Python to manipulate Minecraft. I like to give them a helpful coding environment to work with (Atom Editor) and teach REPL-driven development (via bpython). In Atom I find that the hints/completion works just as effectively as bpython. Luckily, unlike some other statistical analysis tools, Atom is not fooled by import *.

However, lets take this example... In this wrapper they from local_module import * a bunch modules including this list of blocks. Let's ignore the risk of namespace collisions. By doing from mcpi.block import * they make this entire list of obscure types of blocks something that you have to go look at to know what is available. If they had instead used from mcpi import block, then you could type walls = block. and then an autocomplete list would pop up.