[英]Getting the source of an object defined in a Jupyter Notebook
通常,如果要獲取對象的來源,可以通過inspect
模塊獲取:
import inspect
inspect.getsource(MyObject)
但是,在 Jupyter 筆記本中,這不起作用:
import inspect
class Foo:
def __init__(self, info):
self.info = info
a = Foo("hi")
inspect.getsource(a)
拋出錯誤:
---------------------------------------------------------------------------
TypeError Traceback (most recent call last)
<ipython-input-14-048b6f0c2e9b> in <module>()
7 a = Foo("hi")
8
----> 9 inspect.getsource(a)
/usr/lib/python3.6/inspect.py in getsource(object)
963 or code object. The source code is returned as a single string. An
964 OSError is raised if the source code cannot be retrieved."""
--> 965 lines, lnum = getsourcelines(object)
966 return ''.join(lines)
967
/usr/lib/python3.6/inspect.py in getsourcelines(object)
950 raised if the source code cannot be retrieved."""
951 object = unwrap(object)
--> 952 lines, lnum = findsource(object)
953
954 if ismodule(object):
/usr/lib/python3.6/inspect.py in findsource(object)
763 is raised if the source code cannot be retrieved."""
764
--> 765 file = getsourcefile(object)
766 if file:
767 # Invalidate cache if needed.
/usr/lib/python3.6/inspect.py in getsourcefile(object)
679 Return None if no way can be identified to get the source.
680 """
--> 681 filename = getfile(object)
682 all_bytecode_suffixes = importlib.machinery.DEBUG_BYTECODE_SUFFIXES[:]
683 all_bytecode_suffixes += importlib.machinery.OPTIMIZED_BYTECODE_SUFFIXES[:]
/usr/lib/python3.6/inspect.py in getfile(object)
661 return object.co_filename
662 raise TypeError('{!r} is not a module, class, method, '
--> 663 'function, traceback, frame, or code object'.format(object))
664
665 def getmodulename(path):
TypeError: <__main__.Foo object at 0x7fb9130ee518> is not a module, class, method, function, traceback, frame, or code object
如果我試圖找到Foo
的來源(使用inspect.getsource(Foo)
),我得到:
TypeError: <module '__main__'> is a built-in class
如何獲取 Jupyter 筆記本中定義的類的來源?
使用inspect.getsource(inspect.getfile)
我們可以得到一段處理這個的代碼:
...
if isclass(object):
if hasattr(object, '__module__'):
object = sys.modules.get(object.__module__)
if hasattr(object, '__file__'):
return object.__file__
raise TypeError('{!r} is a built-in class'.format(object))
...
似乎在 ipython 或 Jupyter notebook 中,定義的類/函數或__main__
模塊沒有與之關聯的__file__
屬性,因此inspect
無法檢索源文件。 在這種情況下,您可以在單獨的.py
文件中定義類,以便inspect
能夠檢索與其關聯的文件。
我找到了一種“hacky 方式”來獲取 Jupyter Notebook 中的類的源代碼。
假設在一個單元格中有:
class MyClass:
test = 2
def __init__(self):
self.L = 5
def test(self, x):
return True
@classmethod
def forward(cls, x):
return x
然后您可以使用以下方法提取代碼:
import inspect
from IPython.core.magics.code import extract_symbols
obj = MyClass
cell_code = "".join(inspect.linecache.getlines(new_getfile(obj)))
class_code = extract_symbols(cell_code, obj.__name__)[0][0]
print(class_code)
使用從此處定義的new_getfile
:
import inspect, sys
def new_getfile(object, _old_getfile=inspect.getfile):
if not inspect.isclass(object):
return _old_getfile(object)
# Lookup by parent module (as in current inspect)
if hasattr(object, '__module__'):
object_ = sys.modules.get(object.__module__)
if hasattr(object_, '__file__'):
return object_.__file__
# If parent module is __main__, lookup by methods (NEW)
for name, member in inspect.getmembers(object):
if inspect.isfunction(member) and object.__qualname__ + '.' + member.__name__ == member.__qualname__:
return inspect.getfile(member)
else:
raise TypeError('Source for {!r} not found'.format(object))
inspect.getfile = new_getfile
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