29.12. inspect — 审查存活对象 ¶

源代码： Lib/inspect.py

---

The inspect 模块提供几个有用函数以帮助获取有关存活对象 (譬如：模块、类、方法、函数、回溯、框架对象及代码对象) 的信息。例如，它可以帮助审查类的内容、检索方法的源代码、提取和格式化函数的自变量列表，或获取显示详细回溯所需的所有信息。

此模块提供 4 种主要服务：类型校验、获取源代码、审查类和函数及审核解释器堆栈。

29.12.1. 类型和成员 ¶

The getmembers() 函数检索对象 (譬如：类或模块) 的成员。名称以 is 开头的函数主要以第 2 自变量的方便选择形式提供对于 getmembers() . They also help you determine when you can expect to find the following special attributes:

类型	属性	描述
模块	__doc__	文档编制字符串
	__file__	filename (missing for built-in modules)
class	__doc__	文档编制字符串
	__name__	name with which this class was defined
	__qualname__	合格名称
	__module__	name of module in which this class was defined
方法	__doc__	文档编制字符串
	__name__	name with which this method was defined
	__qualname__	合格名称
	__func__	function object containing implementation of method
	__self__	instance to which this method is bound, or None
function	__doc__	文档编制字符串
	__name__	name with which this function was defined
	__qualname__	合格名称
	__code__	code object containing compiled function bytecode
	__defaults__	tuple of any default values for positional or keyword parameters
	__kwdefaults__	mapping of any default values for keyword-only 参数
	__globals__	global namespace in which this function was defined
	__annotations__	mapping of parameters names to annotations; "return" key is reserved for return annotations.
traceback	tb_frame	frame object at this level
	tb_lasti	index of last attempted instruction in bytecode
	tb_lineno	current line number in Python source code
	tb_next	next inner traceback object (called by this level)
frame	f_back	next outer frame object (this frame’s caller)
	f_builtins	builtins namespace seen by this frame
	f_code	code object being executed in this frame
	f_globals	global namespace seen by this frame
	f_lasti	index of last attempted instruction in bytecode
	f_lineno	current line number in Python source code
	f_locals	local namespace seen by this frame
	f_restricted	0 or 1 if frame is in restricted execution mode
	f_trace	tracing function for this frame, or None
code	co_argcount	number of arguments (not including keyword only arguments, * or ** args)
	co_code	string of raw compiled bytecode
	co_cellvars	tuple of names of cell variables (referenced by containing scopes)
	co_consts	tuple of constants used in the bytecode
	co_filename	name of file in which this code object was created
	co_firstlineno	number of first line in Python source code
	co_flags	bitmap of CO_* flags, read more here
	co_lnotab	encoded mapping of line numbers to bytecode indices
	co_freevars	tuple of names of free variables (referenced via a function’s closure)
	co_kwonlyargcount	number of keyword only arguments (not including ** arg)
	co_name	name with which this code object was defined
	co_names	tuple of names of local variables
	co_nlocals	number of local variables
	co_stacksize	virtual machine stack space required
	co_varnames	tuple of names of arguments and local variables
generator	__name__	名称
	__qualname__	合格名称
	gi_frame	frame
	gi_running	is the generator running?
	gi_code	code
	gi_yieldfrom	object being iterated by yield from ，或 None
协程	__name__	名称
	__qualname__	合格名称
	cr_await	object being awaited on, or None
	cr_frame	frame
	cr_running	is the coroutine running?
	cr_code	code
builtin	__doc__	文档编制字符串
	__name__	original name of this function or method
	__qualname__	合格名称
	__self__	instance to which a method is bound, or None

3.5 版改变： 添加 __qualname__ and gi_yieldfrom 属性到生成器。

The __name__ attribute of generators is now set from the function name, instead of the code name, and it can now be modified.

inspect. getmembers ( object [ , predicate ] ) ¶

Return all the members of an object in a list of (name, value) pairs sorted by name. If the optional predicate argument is supplied, only members for which the predicate returns a true value are included.

注意

getmembers() will only return class attributes defined in the metaclass when the argument is a class and those attributes have been listed in the metaclass’ custom __dir__() .

inspect. getmoduleinfo ( path ) ¶

返回 命名元组 ModuleInfo(name, suffix, mode, module_type) of values that describe how Python will interpret the file identified by path if it is a module, or None if it would not be identified as a module. In that tuple, name is the name of the module without the name of any enclosing package, suffix is the trailing part of the file name (which may not be a dot-delimited extension), mode 是 open() mode that would be used ( 'r' or 'rb' )，和 module_type is an integer giving the type of the module. module_type will have a value which can be compared to the constants defined in the imp module; see the documentation for that module for more information on module types.

从 3.3 版起弃用： You may check the file path’s suffix against the supported suffixes listed in importlib.machinery to infer the same information.

inspect. getmodulename ( path ) ¶

Return the name of the module named by the file path , without including the names of enclosing packages. The file extension is checked against all of the entries in importlib.machinery.all_suffixes() . If it matches, the final path component is returned with the extension removed. Otherwise, None 被返回。

注意，此函数 only returns a meaningful name for actual Python modules - paths that potentially refer to Python packages will still return None .

3.3 版改变： This function is now based directly on importlib rather than the deprecated getmoduleinfo() .

inspect. ismodule ( object ) ¶

Return true if the object is a module.

inspect. isclass ( object ) ¶

Return true if the object is a class, whether built-in or created in Python code.

inspect. ismethod ( object ) ¶

Return true if the object is a bound method written in Python.

inspect. isfunction ( object ) ¶

Return true if the object is a Python function, which includes functions created by a lambda 表达式。

inspect. isgeneratorfunction ( object ) ¶

Return true if the object is a Python generator function.

inspect. isgenerator ( object ) ¶

Return true if the object is a generator.

inspect. iscoroutinefunction ( object ) ¶

Return true if the object is a 协程函数 (a function defined with an async def 句法)。

3.5 版新增。

inspect. iscoroutine ( object ) ¶

Return true if the object is a 协程 created by an async def 函数。

3.5 版新增。

inspect. isawaitable ( object ) ¶

Return true if the object can be used in await 表达式。

Can also be used to distinguish generator-based coroutines from regular generators:

def gen():
    yield
@types.coroutine
def gen_coro():
    yield
assert not isawaitable(gen())
assert isawaitable(gen_coro())
						

3.5 版新增。

inspect. istraceback ( object ) ¶

Return true if the object is a traceback.

inspect. isframe ( object ) ¶

Return true if the object is a frame.

inspect. iscode ( object ) ¶

Return true if the object is a code.

inspect. isbuiltin ( object ) ¶

Return true if the object is a built-in function or a bound built-in method.

inspect. isroutine ( object ) ¶

Return true if the object is a user-defined or built-in function or method.

inspect. isabstract ( object ) ¶

Return true if the object is an abstract base class.

inspect. ismethoddescriptor ( object ) ¶

Return true if the object is a method descriptor, but not if ismethod() , isclass() , isfunction() or isbuiltin() are true.

This, for example, is true of int.__add__ . An object passing this test has a __get__() method but not a __set__() method, but beyond that the set of attributes varies. A __name__ attribute is usually sensible, and __doc__ often is.

Methods implemented via descriptors that also pass one of the other tests return false from the ismethoddescriptor() test, simply because the other tests promise more – you can, e.g., count on having the __func__ attribute (etc) when an object passes ismethod() .

inspect. isdatadescriptor ( object ) ¶

Return true if the object is a data descriptor.

Data descriptors have both a __get__ 和 __set__ method. Examples are properties (defined in Python), getsets, and members. The latter two are defined in C and there are more specific tests available for those types, which is robust across Python implementations. Typically, data descriptors will also have __name__ and __doc__ attributes (properties, getsets, and members have both of these attributes), but this is not guaranteed.

inspect. isgetsetdescriptor ( object ) ¶

Return true if the object is a getset descriptor.

CPython 实现细节： getsets are attributes defined in extension modules via PyGetSetDef structures. For Python implementations without such types, this method will always return False .

inspect. ismemberdescriptor ( object ) ¶

Return true if the object is a member descriptor.

CPython 实现细节： Member descriptors are attributes defined in extension modules via PyMemberDef structures. For Python implementations without such types, this method will always return False .

29.12.2. 检索源代码 ¶

inspect. getdoc ( object ) ¶

Get the documentation string for an object, cleaned up with cleandoc() . If the documentation string for an object is not provided and the object is a class, a method, a property or a descriptor, retrieve the documentation string from the inheritance hierarchy.

3.5 版改变： Documentation strings are now inherited if not overridden.

inspect. getcomments ( object ) ¶

Return in a single string any lines of comments immediately preceding the object’s source code (for a class, function, or method), or at the top of the Python source file (if the object is a module). If the object’s source code is unavailable, return None . This could happen if the object has been defined in C or the interactive shell.

inspect. getfile ( object ) ¶

Return the name of the (text or binary) file in which an object was defined. This will fail with a TypeError if the object is a built-in module, class, or function.

inspect. getmodule ( object ) ¶

Try to guess which module an object was defined in.

inspect. getsourcefile ( object ) ¶

Return the name of the Python source file in which an object was defined. This will fail with a TypeError if the object is a built-in module, class, or function.

inspect. getsourcelines ( object ) ¶

Return a list of source lines and starting line number for an object. The argument may be a module, class, method, function, traceback, frame, or code object. The source code is returned as a list of the lines corresponding to the object and the line number indicates where in the original source file the first line of code was found. An OSError is raised if the source code cannot be retrieved.

3.3 版改变： OSError is raised instead of IOError , now an alias of the former.

inspect. getsource ( object ) ¶

Return the text of the source code for an object. The argument may be a module, class, method, function, traceback, frame, or code object. The source code is returned as a single string. An OSError is raised if the source code cannot be retrieved.

3.3 版改变： OSError is raised instead of IOError , now an alias of the former.

inspect. cleandoc ( doc ) ¶

Clean up indentation from docstrings that are indented to line up with blocks of code.

All leading whitespace is removed from the first line. Any leading whitespace that can be uniformly removed from the second line onwards is removed. Empty lines at the beginning and end are subsequently removed. Also, all tabs are expanded to spaces.

29.12.3. Introspecting callables with the Signature object ¶

3.3 版新增。

The Signature object represents the call signature of a callable object and its return annotation. To retrieve a Signature object, use the signature() 函数。

inspect. signature ( callable , * , follow_wrapped=True ) ¶

返回 Signature 对象为给定 callable :

>>> from inspect import signature
>>> def foo(a, *, b:int, **kwargs):
...     pass
>>> sig = signature(foo)
>>> str(sig)
'(a, *, b:int, **kwargs)'
>>> str(sig.parameters['b'])
'b:int'
>>> sig.parameters['b'].annotation
<class 'int'>
							

Accepts a wide range of python callables, from plain functions and classes to functools.partial() 对象。

引发 ValueError if no signature can be provided, and TypeError if that type of object is not supported.

3.5 版新增： follow_wrapped parameter. Pass False to get a signature of callable specifically ( callable.__wrapped__ will not be used to unwrap decorated callables.)

注意

Some callables may not be introspectable in certain implementations of Python. For example, in CPython, some built-in functions defined in C provide no metadata about their arguments.

class inspect. 签名 ( parameters=None , * , return_annotation=Signature.empty ) ¶

A Signature object represents the call signature of a function and its return annotation. For each parameter accepted by the function it stores a Parameter object in its parameters collection.

可选 参数 argument is a sequence of Parameter objects, which is validated to check that there are no parameters with duplicate names, and that the parameters are in the right order, i.e. positional-only first, then positional-or-keyword, and that parameters with defaults follow parameters without defaults.

可选 return_annotation argument, can be an arbitrary Python object, is the “return” annotation of the callable.

Signature objects are immutable 。使用 Signature.replace() to make a modified copy.

3.5 版改变： Signature objects are picklable and hashable.

empty ¶

A special class-level marker to specify absence of a return annotation.

参数 ¶

An ordered mapping of parameters’ names to the corresponding Parameter 对象。

return_annotation ¶

The “return” annotation for the callable. If the callable has no “return” annotation, this attribute is set to Signature.empty .

bind ( *args , **kwargs ) ¶

Create a mapping from positional and keyword arguments to parameters. Returns BoundArguments if *args and **kwargs match the signature, or raises a TypeError .

bind_partial ( *args , **kwargs ) ¶

Works the same way as Signature.bind() , but allows the omission of some required arguments (mimics functools.partial() behavior.) Returns BoundArguments , or raises a TypeError if the passed arguments do not match the signature.

replace ( *[, parameters][, return_annotation] ) ¶

Create a new Signature instance based on the instance replace was invoked on. It is possible to pass different parameters and/or return_annotation to override the corresponding properties of the base signature. To remove return_annotation from the copied Signature, pass in Signature.empty .

>>> def test(a, b):
...     pass
>>> sig = signature(test)
>>> new_sig = sig.replace(return_annotation="new return anno")
>>> str(new_sig)
"(a, b) -> 'new return anno'"
							

classmethod from_callable ( obj , * , follow_wrapped=True ) ¶

返回 Signature (or its subclass) object for a given callable obj . Pass follow_wrapped=False to get a signature of obj without unwrapping its __wrapped__ chain.

This method simplifies subclassing of Signature :

class MySignature(Signature):
    pass
sig = MySignature.from_callable(min)
assert isinstance(sig, MySignature)
							

3.5 版新增。

class inspect. 参数 ( name , kind , * , default=Parameter.empty , annotation=Parameter.empty ) ¶

Parameter objects are immutable . Instead of modifying a Parameter object, you can use Parameter.replace() to create a modified copy.

3.5 版改变： Parameter objects are picklable and hashable.

empty ¶

A special class-level marker to specify absence of default values and annotations.

名称 ¶

The name of the parameter as a string. The name must be a valid Python identifier.

default ¶

The default value for the parameter. If the parameter has no default value, this attribute is set to Parameter.empty .

annotation ¶

The annotation for the parameter. If the parameter has no annotation, this attribute is set to Parameter.empty .

kind ¶

Describes how argument values are bound to the parameter. Possible values (accessible via Parameter ，像 Parameter.KEYWORD_ONLY ):

名称	含义
POSITIONAL_ONLY	Value must be supplied as a positional argument. Python has no explicit syntax for defining positional-only parameters, but many built-in and extension module functions (especially those that accept only one or two parameters) accept them.
POSITIONAL_OR_KEYWORD	Value may be supplied as either a keyword or positional argument (this is the standard binding behaviour for functions implemented in Python.)
VAR_POSITIONAL	A tuple of positional arguments that aren’t bound to any other parameter. This corresponds to a *args parameter in a Python function definition.
KEYWORD_ONLY	Value must be supplied as a keyword argument. Keyword only parameters are those which appear after a * or *args entry in a Python function definition.
VAR_KEYWORD	A dict of keyword arguments that aren’t bound to any other parameter. This corresponds to a **kwargs parameter in a Python function 定义。

Example: print all keyword-only arguments without default values:

>>> def foo(a, b, *, c, d=10):
...     pass
>>> sig = signature(foo)
>>> for param in sig.parameters.values():
...     if (param.kind == param.KEYWORD_ONLY and
...                        param.default is param.empty):
...         print('Parameter:', param)
Parameter: c
							

replace ( *[, name][, kind][, default][, annotation] ) ¶

Create a new Parameter instance based on the instance replaced was invoked on. To override a Parameter attribute, pass the corresponding argument. To remove a default value or/and an annotation from a Parameter, pass Parameter.empty .

>>> from inspect import Parameter
>>> param = Parameter('foo', Parameter.KEYWORD_ONLY, default=42)
>>> str(param)
'foo=42'
>>> str(param.replace()) # Will create a shallow copy of 'param'
'foo=42'
>>> str(param.replace(default=Parameter.empty, annotation='spam'))
"foo:'spam'"
								

3.4 版改变： In Python 3.3 Parameter objects were allowed to have name 设为 None if their kind was set to POSITIONAL_ONLY . This is no longer permitted.

class inspect. BoundArguments ¶

Result of a Signature.bind() or Signature.bind_partial() call. Holds the mapping of arguments to the function’s parameters.

arguments ¶

An ordered, mutable mapping ( collections.OrderedDict ) of parameters’ names to arguments’ values. Contains only explicitly bound arguments. Changes in arguments will reflect in args and kwargs .

Should be used in conjunction with Signature.parameters for any argument processing purposes.

注意

Arguments for which Signature.bind() or Signature.bind_partial() relied on a default value are skipped. However, if needed, use BoundArguments.apply_defaults() to add them.

args ¶

A tuple of positional arguments values. Dynamically computed from the arguments 属性。

kwargs ¶

A dict of keyword arguments values. Dynamically computed from the arguments 属性。

signature ¶

A reference to the parent Signature 对象。

apply_defaults ( ) ¶

Set default values for missing arguments.

For variable-positional arguments ( *args ) the default is an empty tuple.

For variable-keyword arguments ( **kwargs ) the default is an empty dict.

>>> def foo(a, b='ham', *args): pass
>>> ba = inspect.signature(foo).bind('spam')
>>> ba.apply_defaults()
>>> ba.arguments
OrderedDict([('a', 'spam'), ('b', 'ham'), ('args', ())])
								

3.5 版新增。

The args and kwargs properties can be used to invoke functions:

def test(a, *, b):
    ...
sig = signature(test)
ba = sig.bind(10, b=20)
test(*ba.args, **ba.kwargs)
						

另请参阅

PEP 362 - Function Signature Object.

The detailed specification, implementation details and examples.

29.12.4. Classes and functions ¶

inspect. getclasstree ( 类 , unique=False ) ¶

Arrange the given list of classes into a hierarchy of nested lists. Where a nested list appears, it contains classes derived from the class whose entry immediately precedes the list. Each entry is a 2-tuple containing a class and a tuple of its base classes. If the unique argument is true, exactly one entry appears in the returned structure for each class in the given list. Otherwise, classes using multiple inheritance and their descendants will appear multiple times.

inspect. getargspec ( func ) ¶

Get the names and default values of a Python function’s arguments. A 命名元组 ArgSpec(args, varargs, keywords, defaults) 被返回。 args is a list of the argument names. varargs and keywords are the names of the * and ** arguments or None . defaults is a tuple of default argument values or None if there are no default arguments; if this tuple has n elements, they correspond to the last n elements listed in args .

Deprecated since version 3.0: 使用 signature() and Signature Object , which provide a better introspecting API for callables.

inspect. getfullargspec ( func ) ¶

Get the names and default values of a Python function’s arguments. A 命名元组 is returned:

FullArgSpec(args, varargs, varkw, defaults, kwonlyargs, kwonlydefaults, annotations)

args is a list of the argument names. varargs and varkw are the names of the * and ** arguments or None . defaults 是 n -tuple of the default values of the last n arguments, or None if there are no default arguments. kwonlyargs is a list of keyword-only argument names. kwonlydefaults is a dictionary mapping names from kwonlyargs to defaults. annotations is a dictionary mapping argument names to annotations.

The first four items in the tuple correspond to getargspec() .

3.4 版改变： This function is now based on signature() , but still ignores __wrapped__ attributes and includes the already bound first parameter in the signature output for bound methods.

从 3.5 版起弃用： 使用 signature() and Signature Object , which provide a better introspecting API for callables.

inspect. getargvalues ( frame ) ¶

Get information about arguments passed into a particular frame. A 命名元组 ArgInfo(args, varargs, keywords, locals) 被返回。 args is a list of the argument names. varargs and keywords are the names of the * and ** arguments or None . locals is the locals dictionary of the given frame.

注意

This function was inadvertently marked as deprecated in Python 3.5.

inspect. formatargspec ( args [ , varargs , varkw , defaults , kwonlyargs , kwonlydefaults , annotations [ , formatarg , formatvarargs , formatvarkw , formatvalue , formatreturns , formatannotations ] ] ) ¶

Format a pretty argument spec from the values returned by getargspec() or getfullargspec() .

The first seven arguments are ( args , varargs , varkw , defaults , kwonlyargs , kwonlydefaults , annotations ).

The other six arguments are functions that are called to turn argument names, * argument name, ** argument name, default values, return annotation and individual annotations into strings, respectively.

例如：

>>> from inspect import formatargspec, getfullargspec
>>> def f(a: int, b: float):
...     pass
...
>>> formatargspec(*getfullargspec(f))
'(a: int, b: float)'
								

从 3.5 版起弃用： 使用 signature() and Signature Object , which provide a better introspecting API for callables.

inspect. formatargvalues ( args [ , varargs , varkw , locals , formatarg , formatvarargs , formatvarkw , formatvalue ] ) ¶

Format a pretty argument spec from the four values returned by getargvalues() . The format* arguments are the corresponding optional formatting functions that are called to turn names and values into strings.

注意

This function was inadvertently marked as deprecated in Python 3.5.

inspect. getmro ( cls ) ¶

Return a tuple of class cls’s base classes, including cls, in method resolution order. No class appears more than once in this tuple. Note that the method resolution order depends on cls’s type. Unless a very peculiar user-defined metatype is in use, cls will be the first element of the tuple.

inspect. getcallargs ( func , *args , **kwds ) ¶

Bind the args and kwds to the argument names of the Python function or method func , as if it was called with them. For bound methods, bind also the first argument (typically named self ) to the associated instance. A dict is returned, mapping the argument names (including the names of the * and ** arguments, if any) to their values from args and kwds . In case of invoking func incorrectly, i.e. whenever func(*args, **kwds) would raise an exception because of incompatible signature, an exception of the same type and the same or similar message is raised. For example:

>>> from inspect import getcallargs
>>> def f(a, b=1, *pos, **named):
...     pass
>>> getcallargs(f, 1, 2, 3) == {'a': 1, 'named': {}, 'b': 2, 'pos': (3,)}
True
>>> getcallargs(f, a=2, x=4) == {'a': 2, 'named': {'x': 4}, 'b': 1, 'pos': ()}
True
>>> getcallargs(f)
Traceback (most recent call last):
...
TypeError: f() missing 1 required positional argument: 'a'
								

3.2 版新增。

从 3.5 版起弃用： 使用 Signature.bind() and Signature.bind_partial() 代替。

inspect. getclosurevars ( func ) ¶

Get the mapping of external name references in a Python function or method func to their current values. A 命名元组 ClosureVars(nonlocals, globals, builtins, unbound) 被返回。 nonlocals maps referenced names to lexical closure variables, globals to the function’s module globals and builtins to the builtins visible from the function body. unbound is the set of names referenced in the function that could not be resolved at all given the current module globals and builtins.

TypeError 被引发若 func is not a Python function or method.

3.3 版新增。

inspect. unwrap ( func , * , stop=None ) ¶

Get the object wrapped by func . It follows the chain of __wrapped__ attributes returning the last object in the chain.

stop is an optional callback accepting an object in the wrapper chain as its sole argument that allows the unwrapping to be terminated early if the callback returns a true value. If the callback never returns a true value, the last object in the chain is returned as usual. For example, signature() uses this to stop unwrapping if any object in the chain has a __signature__ attribute defined.

ValueError is raised if a cycle is encountered.

3.4 版新增。

29.12.5. The interpreter stack ¶

When the following functions return “frame records,” each record is a 命名元组 FrameInfo(frame, filename, lineno, function, code_context, index) . The tuple contains the frame object, the filename, the line number of the current line, the function name, a list of lines of context from the source code, and the index of the current line within that list.

3.5 版改变： Return a named tuple instead of a tuple.

注意

Keeping references to frame objects, as found in the first element of the frame records these functions return, can cause your program to create reference cycles. Once a reference cycle has been created, the lifespan of all objects which can be accessed from the objects which form the cycle can become much longer even if Python’s optional cycle detector is enabled. If such cycles must be created, it is important to ensure they are explicitly broken to avoid the delayed destruction of objects and increased memory consumption which occurs.

Though the cycle detector will catch these, destruction of the frames (and local variables) can be made deterministic by removing the cycle in a finally clause. This is also important if the cycle detector was disabled when Python was compiled or using gc.disable() 。例如：

def handle_stackframe_without_leak():
    frame = inspect.currentframe()
    try:
        # do something with the frame
    finally:
        del frame
						

If you want to keep the frame around (for example to print a traceback later), you can also break reference cycles by using the frame.clear() 方法。

可选 context argument supported by most of these functions specifies the number of lines of context to return, which are centered around the current line.

inspect. getframeinfo ( frame , context=1 ) ¶

Get information about a frame or traceback object. A 命名元组 Traceback(filename, lineno, function, code_context, index) 被返回。

inspect. getouterframes ( frame , context=1 ) ¶

Get a list of frame records for a frame and all outer frames. These frames represent the calls that lead to the creation of frame . The first entry in the returned list represents frame ; the last entry represents the outermost call on frame ‘s stack.

3.5 版改变： 列表化的 命名元组 FrameInfo(frame, filename, lineno, function, code_context, index) 被返回。

inspect. getinnerframes ( traceback , context=1 ) ¶

Get a list of frame records for a traceback’s frame and all inner frames. These frames represent calls made as a consequence of frame . The first entry in the list represents traceback ; the last entry represents where the exception was raised.

3.5 版改变： 列表化的 命名元组 FrameInfo(frame, filename, lineno, function, code_context, index) 被返回。

inspect. currentframe ( ) ¶

返回用于调用者堆栈帧的帧对象。

CPython 实现细节： This function relies on Python stack frame support in the interpreter, which isn’t guaranteed to exist in all implementations of Python. If running in an implementation without Python stack frame support this function returns None .

inspect. stack ( context=1 ) ¶

Return a list of frame records for the caller’s stack. The first entry in the returned list represents the caller; the last entry represents the outermost call on the stack.

3.5 版改变： 列表化的 命名元组 FrameInfo(frame, filename, lineno, function, code_context, index) 被返回。

inspect. trace ( context=1 ) ¶

Return a list of frame records for the stack between the current frame and the frame in which an exception currently being handled was raised in. The first entry in the list represents the caller; the last entry represents where the exception was raised.

3.5 版改变： 列表化的 命名元组 FrameInfo(frame, filename, lineno, function, code_context, index) 被返回。

29.12.6. Fetching attributes statically ¶

Both getattr() and hasattr() can trigger code execution when fetching or checking for the existence of attributes. Descriptors, like properties, will be invoked and __getattr__() and __getattribute__() may be called.

For cases where you want passive introspection, like documentation tools, this can be inconvenient. getattr_static() has the same signature as getattr() but avoids executing code when it fetches attributes.

inspect. getattr_static ( obj , attr , default=None ) ¶

Retrieve attributes without triggering dynamic lookup via the descriptor protocol, __getattr__() or __getattribute__() .

Note: this function may not be able to retrieve all attributes that getattr can fetch (like dynamically created attributes) and may find attributes that getattr can’t (like descriptors that raise AttributeError). It can also return descriptors objects instead of instance members.

If the instance __dict__ is shadowed by another member (for example a property) then this function will be unable to find instance members.

3.2 版新增。

getattr_static() does not resolve descriptors, for example slot descriptors or getset descriptors on objects implemented in C. The descriptor object is returned instead of the underlying attribute.

You can handle these with code like the following. Note that for arbitrary getset descriptors invoking these may trigger code execution:

# example code for resolving the builtin descriptor types
class _foo:
    __slots__ = ['foo']
slot_descriptor = type(_foo.foo)
getset_descriptor = type(type(open(__file__)).name)
wrapper_descriptor = type(str.__dict__['__add__'])
descriptor_types = (slot_descriptor, getset_descriptor, wrapper_descriptor)
result = getattr_static(some_object, 'foo')
if type(result) in descriptor_types:
    try:
        result = result.__get__()
    except AttributeError:
        # descriptors can raise AttributeError to
        # indicate there is no underlying value
        # in which case the descriptor itself will
        # have to do
        pass
							

29.12.7. Current State of Generators and Coroutines ¶

When implementing coroutine schedulers and for other advanced uses of generators, it is useful to determine whether a generator is currently executing, is waiting to start or resume or execution, or has already terminated. getgeneratorstate() allows the current state of a generator to be determined easily.

inspect. getgeneratorstate ( generator ) ¶

Get current state of a generator-iterator.

Possible states are:

• GEN_CREATED: Waiting to start execution.
• GEN_RUNNING: Currently being executed by the interpreter.
• GEN_SUSPENDED: Currently suspended at a yield expression.
• GEN_CLOSED: Execution has completed.

3.2 版新增。

inspect. getcoroutinestate ( 协程 ) ¶

Get current state of a coroutine object. The function is intended to be used with coroutine objects created by async def functions, but will accept any coroutine-like object that has cr_running and cr_frame 属性。

Possible states are:

• CORO_CREATED: Waiting to start execution.
• CORO_RUNNING: Currently being executed by the interpreter.
• CORO_SUSPENDED: Currently suspended at an await expression.
• CORO_CLOSED: Execution has completed.

3.5 版新增。

The current internal state of the generator can also be queried. This is mostly useful for testing purposes, to ensure that internal state is being updated as expected:

inspect. getgeneratorlocals ( generator ) ¶

Get the mapping of live local variables in generator to their current values. A dictionary is returned that maps from variable names to values. This is the equivalent of calling locals() in the body of the generator, and all the same caveats apply.

若 generator 是 generator with no currently associated frame, then an empty dictionary is returned. TypeError 被引发若 generator is not a Python generator object.

CPython 实现细节： This function relies on the generator exposing a Python stack frame for introspection, which isn’t guaranteed to be the case in all implementations of Python. In such cases, this function will always return an empty dictionary.

3.3 版新增。

inspect. getcoroutinelocals ( 协程 ) ¶

This function is analogous to getgeneratorlocals() , but works for coroutine objects created by async def 函数。

3.5 版新增。

29.12.8. Code Objects Bit Flags ¶

Python code objects have a co_flags attribute, which is a bitmap of the following flags:

inspect. CO_OPTIMIZED ¶

The code object is optimized, using fast locals.

inspect. CO_NEWLOCALS ¶

If set, a new dict will be created for the frame’s f_locals when the code object is executed.

inspect. CO_VARARGS ¶

The code object has a variable positional parameter ( *args 像)。

inspect. CO_VARKEYWORDS ¶

The code object has a variable keyword parameter ( **kwargs 像)。

inspect. CO_NESTED ¶

The flag is set when the code object is a nested function.

inspect. CO_GENERATOR ¶

The flag is set when the code object is a generator function, i.e. a generator object is returned when the code object is executed.

inspect. CO_NOFREE ¶

The flag is set if there are no free or cell variables.

inspect. CO_COROUTINE ¶

The flag is set when the code object is a coroutine function, i.e. a coroutine object is returned when the code object is executed. See PEP 492 了解更多细节。

3.5 版新增。

inspect. CO_ITERABLE_COROUTINE ¶

Used to turn generators into generator-based coroutines. Generator objects with this flag can be used in await expression, and can yield from coroutine objects. See PEP 492 了解更多细节。

3.5 版新增。

注意

The flags are specific to CPython, and may not be defined in other Python implementations. Furthermore, the flags are an implementation detail, and can be removed or deprecated in future Python releases. It’s recommended to use public APIs from the inspect module for any introspection needs.

29.12.9. Command Line Interface ¶

The inspect module also provides a basic introspection capability from the command line.

By default, accepts the name of a module and prints the source of that module. A class or function within the module can be printed instead by appended a colon and the qualified name of the target object.

--details ¶

Print information about the specified object rather than the source code

内容表

• 29.12. inspect — 审查存活对象
  • 29.12.1. 类型和成员
  • 29.12.2. 检索源代码
  • 29.12.3. Introspecting callables with the Signature object
  • 29.12.4. Classes and functions
  • 29.12.5. The interpreter stack
  • 29.12.6. Fetching attributes statically
  • 29.12.7. Current State of Generators and Coroutines
  • 29.12.8. Code Objects Bit Flags
  • 29.12.9. Command Line Interface

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