pollution of the global name space

Off the top of my head a) Nothing prevents the writer of the module you are importing from overriding symbols that you expect b) In many cases increased load times. c) Irrelevant symbols present in scope when debugging d) Makes the order of import statements important, because potentially different modules might be providing the same variable name

because this might mess up your script by either overwriting something that's already defined, or you might accidentally overwrite something that is 'hidden' behind the '* '.

somewhat naive example:

    >>> time = 'blah'
    >>> time
    'blah'
    >>> from datetime import *
    >>> time
    <type 'datetime.time'>
    >>>

Because it leads to namespace pollution and hard-to-track-down bugs.

It's especially bad in this case where adding an executable in the system can suddenly shadow any built-in name (e.g. imagine someone adds a "print" or "sys" executable).

makes references ambiguous to anyone but the interpreter

let's say you have

from a import foo from b import *

what does 'foo' refer to? 'b' could contain 'foo', which would overwrite your previous reference to 'a.foo'. its hard to figure out what 'foo' now refers to from inspecting the code. its better to be explicit:

from a import foo from b import bar, baz