从字符串名称在Python中加载类

Question

我有一系列的类名，想要全部检查它们并将它们导入。 这个怎么做：

CName='Class_blahblah'
from eval(CName) import *  

这就是我得到的：

 SyntaxError: invalid syntax

确切地说：我有几个类是在FEA软件中的IDE中运行的，我为每个类都做了类似的事情：

if 'Class_SetSurfPart' in sys.modules:  
    del sys.modules['Class_SetSurfPart']
    print 'old module Class_SetSurfPart deleted'
    from Class_SetSurfPart import *
    reload(sys.modules['Class_SetSurfPart'])
else:
    from Class_SetSurfPart import *

但我想将所有类名放在一个列表中，并将其作为循环而不是对所有类都这样做。

Answer 1

放置钥匙可能是一个好主意

sys.modules

在这样的列表中：

#I'm assuming that you've already made a list of the classes you want to be 
#checking for in a list. I'll call that list classes.
for name in classes:
    if name in keys:
        del sys.modules[name]  #remember that this does not delete it permanently.
        print "Old module {} deleted".format(name)
        name = __import__(name)
        reload(name)
    else:
        __import__(name)

请记住，每个项目都以字符串类型存储。

 #I'm assuming that you've already made a list of the classes you want to be #checking for in a list. I'll call that list classes. for name in classes: if name in keys: del sys.modules[name] #remember that this does not delete it permanently. print "Old module {} deleted".format(name) name = __import__(name) reload(name) else: __import__(name) 

Answer 2

您需要importlib.import_module ：

bruno@bigb:~/Work/playground/imps$ ls pack/
__init__.py  stuff.py  
bruno@bigb:~/Work/playground/imps$ cat pack/stuff.py
class Foo(object):
    pass
bruno@bigb:~/Work/playground/imps$ python
Python 2.7.6 (default, Jun 22 2015, 17:58:13) 
>>> import importlib
>>> module = importlib.import_module("pack.stuff")
>>> module
<module 'pack.stuff' from 'pack/stuff.pyc'>
>>> # now you can either use getattr() or directly refer to `module.Foo`: 
>>> cls = getattr(module, "Foo")
>>> cls
<class 'pack.stuff.Foo'>
>>> module.Foo
<class 'pack.stuff.Foo'>
>>> module.Foo is cls
True