blocks|key|690751|text|importlib.import_module就是你要找的东西。它返回导入的模块。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|690752|import+importlib

mymodule+=+importlib.import_module('matplotlib.text')|code-block|syntax|javascript|690753|然后，您可以访问模块中的任何内容，如mymodule.myclass、mymodule.myfunction等。|690754|entityMap|0|LINK|mutability|MUTABLE|url|https://docs.python.org/library/importlib.html#importlib.import_module^0|0|N|0|N|0|0|0|I|G|Z|J|0^^$0|@$1|2|3|4|5|6|7|U|8|@$9|V|A|W|B|C]]|D|@$9|X|A|Y|1|Z]]|E|$]]|$1|F|3|G|5|H|7|10|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|11|8|@$9|12|A|13|B|C]|$9|14|A|15|B|C]]|D|@]|E|$]]|$1|M|3|-4|5|6|7|16|8|@]|D|@]|E|$]]]|N|$O|$5|P|Q|R|E|$S|T]]]]

<a href="https://docs.python.org/library/importlib.html#importlib.import_module" rel="nofollow noreferrer"><code>importlib.import_module</code></a> is what you are looking for. It returns the imported module.
<pre><code>import importlib

mymodule = importlib.import_module('matplotlib.text')
</code></pre>
You can thereafter access anything in the module as <code>mymodule.myclass</code>, <code>mymodule.myfunction</code>, etc.

blocks|key|474710|text|我花了一些时间尝试从列表中导入模块，这是我完成大部分工作的线索-但我没有掌握___import____的用法-|type|unstyled|depth|inlineStyleRanges|entityRanges|data|474711|因此，下面介绍如何从字符串导入模块，并获得与导入相同的行为。并尝试/排除错误情况。:)|474712|++pipmodules+=+['pycurl',+'ansible',+'bad_module_no_beer']
++for+module+in+pipmodules:
++++++try:
++++++++++#+because+we+want+to+import+using+a+variable,+do+it+this+way
++++++++++module_obj+=+__import__(module)
++++++++++#+create+a+global+object+containging+our+module
++++++++++globals()[module]+=+module_obj
++++++except+ImportError:
++++++++++sys.stderr.write("ERROR:+missing+python+module:+"+%2B+module+%2B+"\n")
++++++++++sys.exit(1)|code-block|syntax|javascript|474713|是的，对于python+2.7>，你有其他的选择--但是对于2.6<，这是可行的。|474714|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|N|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|O|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|P|8|@]|9|@]|A|$]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

spent some time trying to import modules from a list, and this is the thread that got me most of the way there - but I didnt grasp the use of ___import____ - 

so here's how to import a module from a string, and get the same behavior as just import. And try/except the error case, too. :)

<pre><code> pipmodules = ['pycurl', 'ansible', 'bad_module_no_beer']
 for module in pipmodules:
 try:
 # because we want to import using a variable, do it this way
 module_obj = __import__(module)
 # create a global object containging our module
 globals()[module] = module_obj
 except ImportError:
 sys.stderr.write("ERROR: missing python module: " + module + "\n")
 sys.exit(1)
</code></pre>

and yes, for python 2.7> you have other options - but for 2.6&lt;, this works.

blocks|key|474773|text|我开发了以下3个有用的函数：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|474774|def+loadModule(moduleName):
++++module+=+None
++++try:
++++++++import+sys
++++++++del+sys.modules[moduleName]
++++except+BaseException+as+err:
++++++++pass
++++try:
++++++++import+importlib
++++++++module+=+importlib.import_module(moduleName)
++++except+BaseException+as+err:
++++++++serr+=+str(err)
++++++++print("Error+to+load+the+module+'"+%2B+moduleName+%2B+"':+"+%2B+serr)
++++return+module

def+reloadModule(moduleName):
++++module+=+loadModule(moduleName)
++++moduleName,+modulePath+=+str(module).replace("'+from+'",+"%7C%7C").replace("<module+'",+'').replace("'>",+'').split("%7C%7C")
++++if+(modulePath.endswith(".pyc")):
++++++++import+os
++++++++os.remove(modulePath)
++++++++module+=+loadModule(moduleName)
++++return+module

def+getInstance(moduleName,+param1,+param2,+param3):
++++module+=+reloadModule(moduleName)
++++instance+=+eval("module."+%2B+moduleName+%2B+"(param1,+param2,+param3)")
++++return+instance|code-block|syntax|javascript|474775|每次我想要重新加载一个新的实例时，我只需要像这样调用getInstance()：|474776|myInstance+=+getInstance("MyModule",+myParam1,+myParam2,+myParam3)|474777|最后，我可以调用新实例中的所有函数：|474778|myInstance.aFunction()|474779|这里唯一的特点是定制实例的参数列表(param1、param2、param3)。|474780|entityMap^0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|U|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|W|8|@]|9|@]|A|$]]|$1|M|3|N|5|D|7|X|8|@]|9|@]|A|$E|F]]|$1|O|3|P|5|6|7|Y|8|@]|9|@]|A|$]]|$1|Q|3|-4|5|6|7|Z|8|@]|9|@]|A|$]]]|R|$]]

I developed these 3 useful functions:

<pre class="lang-py prettyprint-override"><code>def loadModule(moduleName):
 module = None
 try:
 import sys
 del sys.modules[moduleName]
 except BaseException as err:
 pass
 try:
 import importlib
 module = importlib.import_module(moduleName)
 except BaseException as err:
 serr = str(err)
 print("Error to load the module '" + moduleName + "': " + serr)
 return module

def reloadModule(moduleName):
 module = loadModule(moduleName)
 moduleName, modulePath = str(module).replace("' from '", "||").replace("&lt;module '", '').replace("'&gt;", '').split("||")
 if (modulePath.endswith(".pyc")):
 import os
 os.remove(modulePath)
 module = loadModule(moduleName)
 return module

def getInstance(moduleName, param1, param2, param3):
 module = reloadModule(moduleName)
 instance = eval("module." + moduleName + "(param1, param2, param3)")
 return instance
</code></pre>

And everytime I want to reload a new instance I just have to call getInstance() like this:

<pre class="lang-py prettyprint-override"><code>myInstance = getInstance("MyModule", myParam1, myParam2, myParam3)
</code></pre>

Finally I can call all the functions inside the new Instance:

<pre class="lang-py prettyprint-override"><code>myInstance.aFunction()
</code></pre>

The only specificity here is to customize the params list (param1, param2, param3) of your instance.

blocks|key|474842|text|除了使用importlib之外，还可以使用exec方法从字符串变量导入模块。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|474843|这里我展示了一个使用exec方法从itertools包导入combinations方法的示例：|474844|MODULES+=+[
++++['itertools','combinations'],
]

for+ITEM+in+MODULES:
++++import_str+=+"from+{0}+import+{1}".format(ITEM[0],',+'.join(str(i)+for+i+in+ITEM[1:]))
++++exec(import_str)

ar+=+list(combinations([1,+2,+3,+4],+2))
for+elements+in+ar:
++++print(elements)|code-block|syntax|javascript|474845|输出：|474846|(1,+2)
(1,+3)
(1,+4)
(2,+3)
(2,+4)
(3,+4)|474847|entityMap^0|4|9|L|4|0|A|4|H|9|T|C|0|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@$9|T|A|U|B|C]|$9|V|A|W|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|X|8|@$9|Y|A|Z|B|C]|$9|10|A|11|B|C]|$9|12|A|13|B|C]]|D|@]|E|$]]|$1|H|3|I|5|J|7|14|8|@]|D|@]|E|$K|L]]|$1|M|3|N|5|6|7|15|8|@]|D|@]|E|$]]|$1|O|3|P|5|J|7|16|8|@]|D|@]|E|$K|L]]|$1|Q|3|-4|5|6|7|17|8|@]|D|@]|E|$]]]|R|$]]

Apart from using the <code>importlib</code> one can also use <code>exec</code> method to import a module from a string variable.

Here I am showing an example of importing the <code>combinations</code> method from <code>itertools</code> package using the <code>exec</code> method:

<pre><code>MODULES = [
 ['itertools','combinations'],
]

for ITEM in MODULES:
 import_str = "from {0} import {1}".format(ITEM[0],', '.join(str(i) for i in ITEM[1:]))
 exec(import_str)

ar = list(combinations([1, 2, 3, 4], 2))
for elements in ar:
 print(elements)
</code></pre>

Output:

<pre><code>(1, 2)
(1, 3)
(1, 4)
(2, 3)
(2, 4)
(3, 4)
</code></pre>

I'm working on a documentation (personal) for nested matplotlib (MPL) library, which differs from MPL own provided, by interested submodule packages. I'm writing Python script which I hope will automate document generation from future MPL releases. 
I selected interested submodules/packages and want to list their main classes from which I'll generate list and process it with <code>pydoc</code> 

Problem is that I can't find a way to instruct Python to load submodule from string. Here is example of what I tried:

<pre><code>import matplotlib.text as text
x = dir(text)
</code></pre>

. 

<pre><code>i = __import__('matplotlib.text')
y = dir(i)
</code></pre>

.

<pre><code>j = __import__('matplotlib')
z = dir(j)
</code></pre>

And here is 3 way comparison of above lists through pprint:

<img src="https://i.stack.imgur.com/3n7pT.png" alt="enter image description here">

I don't understand what's loaded in <code>y</code> object - it's base <code>matplotlib</code> plus something else, but it lack information that I wanted and that is main classes from <code>matplotlib.text</code> package. It's top blue coloured part on screenshot (<code>x</code> list)

Please don't suggest Sphinx as different approach.

import module from string variable

Python

我正在为嵌套的matplotlib ( MPL )库编写文档(个人)，它不同于MPL自己提供的，由感兴趣的子模块包提供。我正在编写Python脚本，我希望它能从未来的MPL版本自动生成文档。我选择了感兴趣的子模块/包，并希望列出它们的主类，我将从这些主类中生成列表并使用pydoc对其进行处理问题是我找不到一种方法来指示...

问从字符串变量导入模块
EN

社区

活动

资源

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问从字符串变量导入模块EN

社区

活动

资源

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问从字符串变量导入模块
EN