python - 如何在 Python 中进行多次导入？

Question

在 Ruby 中，我不会多次重复“require”（Python 中的“import”）这个词

%w{lib1 lib2 lib3 lib4 lib5}.each { |x| require x }

所以它会遍历一组“libs”和“require”（导入）它们中的每一个。现在我正在编写一个 Python 脚本，我想做类似的事情。有没有办法，或者我需要为所有这些写“导入”。

直截了当的“翻译”类似于以下代码。无论如何，由于 Python 不导入命名为字符串的库，因此它不起作用。

requirements = [lib1, lib2, lib3, lib4, lib5]
for lib in requirements:
    import lib

提前致谢

Answer 1

For known module, just separate them by commas:

import lib1, lib2, lib3, lib4, lib5

If you really need to programmatically import based on dynamic variables, a literal translation of your ruby would be:

modnames = "lib1 lib2 lib3 lib4 lib5".split()
for lib in modnames:
    globals()[lib] = __import__(lib)

Though there's no need for this in your example.

Answer 2

试试这个：

import lib1, lib2, lib3, lib4, lib5

您还可以通过这种方式更改导入它们的名称，如下所示：

import lib1 as l1, lib2 as l2, lib3, lib4 as l4, lib5

Answer 3

import lib1, lib2, lib3, lib4, lib5

Answer 4

if you want multi-line:

from englishapps.multiple.mainfile import (
    create_multiple_,
    get_data_for_multiple
)

Answer 5

__import__您可以使用该函数从包含模块名称的字符串导入。

requirements = [lib1, lib2, lib3, lib4, lib5]
for lib in requirements:
    x = __import__(lib)

Answer 6

You can use __import__ if you have a list of strings that represent modules, but it's probably cleaner if you follow the hint in the documentation and use importlib.import_module directly:

import importlib
requirements = [lib1, lib2, lib3, lib4, lib5]
imported_libs = {lib: importlib.import_module(lib) for lib in requirements}

You don't have the imported libraries as variables available this way but you could access them through the imported_libs dictionary:

>>> requirements = ['sys', 'itertools', 'collections', 'pickle']
>>> imported_libs = {lib: importlib.import_module(lib) for lib in requirements}
>>> imported_libs
{'collections': <module 'collections' from 'lib\\collections\\__init__.py'>,
 'itertools': <module 'itertools' (built-in)>,
 'pickle': <module 'pickle' from 'lib\\pickle.py'>,
 'sys': <module 'sys' (built-in)>}

>>> imported_libs['sys'].hexversion
50660592

You could also update your globals and then use them like they were imported "normally":

>>> globals().update(imported_libs)
>>> sys
<module 'sys' (built-in)>

Answer 7

I just learned from a coworker today that, according to the PEP 8 Style Guide, imports in Python should actually be written on separate lines:

import os
import sys

The style guide calls import sys, os wrong.