inspect — Inspect live objects检查活动对象

Source code: Lib/inspect.py

The inspect module provides several useful functions to help get information about live objects such as modules, classes, methods, functions, tracebacks, frame objects, and code objects. inspect模块提供了几个有用的函数，以帮助获取有关活动对象的信息，例如模块、类、方法、函数、回溯、框架对象和代码对象。For example, it can help you examine the contents of a class, retrieve the source code of a method, extract and format the argument list for a function, or get all the information you need to display a detailed traceback.例如，它可以帮助您检查类的内容，检索方法的源代码，提取并格式化函数的参数列表，或者获取显示详细回溯所需的所有信息。

There are four main kinds of services provided by this module: type checking, getting source code, inspecting classes and functions, and examining the interpreter stack.该模块提供四种主要服务：类型检查、获取源代码、检查类和函数以及检查解释器堆栈。

Types and members类型和成员

The getmembers() function retrieves the members of an object such as a class or module. getmembers()函数的作用是：检索类或模块等对象的成员。The functions whose names begin with “is” are mainly provided as convenient choices for the second argument to getmembers(). 名称以“is”开头的函数主要作为getmembers()的第二个参数的方便选择。They also help you determine when you can expect to find the following special attributes:它们还可以帮助您确定何时可以找到以下特殊属性：

Type类型

Attribute属性

Description描述

module

__doc__

documentation string文档字符串

__file__

filename (missing for built-in modules)文件名（内置模块缺少）

class

__doc__

documentation string文档字符串

__name__

name with which this class was defined定义此类时使用的名称

__qualname__

qualified name限定名

__module__

name of module in which this class was defined定义此类的模块的名称

method

__doc__

documentation string文档字符串

__name__

name with which this method was defined用于定义此方法的名称

__qualname__

qualified name限定名

__func__

function object containing implementation of method包含方法实现的函数对象

__self__

instance to which this method is bound, or None此方法绑定到的实例，或None

__module__

name of module in which this method was defined定义此方法的模块的名称

function

__doc__

documentation string文档字符串

__name__

name with which this function was defined定义此函数的名称

__qualname__

qualified name限定名

__code__

code object containing compiled function bytecode包含编译函数字节码的代码对象

__defaults__

tuple of any default values for positional or keyword parameters位置参数或关键字参数的任何默认值的元组

__kwdefaults__

mapping of any default values for keyword-only parameters仅关键字参数的任何默认值的映射

__globals__

global namespace in which this function was defined定义此函数的全局命名空间

__builtins__

builtins namespace内置名称空间

__annotations__

mapping of parameters names to annotations; "return" key is reserved for return annotations.将参数名称映射到注释；"return"键是为return注释保留的。

__module__

name of module in which this function was defined定义此函数的模块的名称

traceback

tb_frame

frame object at this level此级别的框架对象

tb_lasti

index of last attempted instruction in bytecode字节码中最后尝试的指令的索引

tb_lineno

current line number in Python source codePython源代码中的当前行号

tb_next

next inner traceback object (called by this level)下一个内部回溯对象（由该级别调用）

frame

f_back

next outer frame object (this frame’s caller)下一个外部框架对象（此框架的调用者）

f_builtins

builtins namespace seen by this frame此框架看到的内置名称空间

f_code

code object being executed in this frame在此框架中执行的代码对象

f_globals

global namespace seen by this frame此框架看到的全局命名空间

f_lasti

index of last attempted instruction in bytecode字节码中最后尝试的指令的索引

f_lineno

current line number in Python source codePython源代码中的当前行号

f_locals

local namespace seen by this frame此框架看到的本地命名空间

f_trace

tracing function for this frame, or None此帧的跟踪功能，或None

code

co_argcount

number of arguments (not including keyword only arguments, * or ** args)参数数量（不包括仅关键字参数，*或**参数）

co_code

string of raw compiled bytecode原始编译字节码字符串

co_cellvars

tuple of names of cell variables (referenced by containing scopes)单元变量名称的元组（由包含范围引用）

co_consts

tuple of constants used in the bytecode字节码中使用的常量元组

co_filename

name of file in which this code object was created创建此代码对象的文件名

co_firstlineno

number of first line in Python source codePython源代码中第一行的编号

co_flags

bitmap of CO_* flags, read more hereCO_*标志位图，请阅读此处

co_lnotab

encoded mapping of line numbers to bytecode indices行号到字节码索引的编码映射

co_freevars

tuple of names of free variables (referenced via a function’s closure)自由变量名称的元组（通过函数的闭包引用）

co_posonlyargcount

number of positional only arguments仅位置参数的数量

co_kwonlyargcount

number of keyword only arguments (not including ** arg)仅关键字参数的数量（不包括**参数）

co_name

name with which this code object was defined用于定义此代码对象的名称

co_names

tuple of names other than arguments and function locals参数和函数局部变量以外的名称元组

co_nlocals

number of local variables局部变量数

co_stacksize

virtual machine stack space required需要虚拟机堆栈空间

co_varnames

tuple of names of arguments and local variables参数和局部变量名称的元组

generator

__name__

name名称

__qualname__

qualified name限定名称

gi_frame

frame框架

gi_running

is the generator running?发电机在运行吗？

gi_code

code

gi_yieldfrom

object being iterated by yield from, or None通过yield from或None迭代的对象

coroutine

__name__

name名称

__qualname__

qualified name限定名称

cr_await

object being awaited on, or None上等待的对象，或None

cr_frame

frame

cr_running

is the coroutine running?郊游在进行吗？

cr_code

code

cr_origin

where coroutine was created, or None. See sys.set_coroutine_origin_tracking_depth()创建协同程序的位置，或None。请参见sys.set_coroutine_origin_tracking_depth()

builtin内置的

__doc__

documentation string文档字符串

__name__

original name of this function or method此函数或方法的原始名称

__qualname__

qualified name限定名称

__self__

instance to which a method is bound, or None方法绑定到的实例，或None

Changed in version 3.5:版本3.5中更改： Add __qualname__ and gi_yieldfrom attributes to generators.将__qualiname__和gi_yieldfrom属性添加到生成器中。

The __name__ attribute of generators is now set from the function name, instead of the code name, and it can now be modified.生成器的__name__属性现在是从函数名而不是代码名设置的，现在可以对其进行修改。

Changed in version 3.7:版本3.7中更改： Add cr_origin attribute to coroutines.将cr_origin属性添加到协同程序。

Changed in version 3.10:版本3.10中更改： Add __builtins__ attribute to functions.将__builtins__属性添加到函数中。

inspect.getmembers(object[, predicate])

Return all the members of an object in a list of (name, value) pairs sorted by name. 返回按名称排序的(name, value)对列表中对象的所有成员。If the optional predicate argument—which will be called with the value object of each member—is supplied, only members for which the predicate returns a true value are included.如果提供了将与每个成员的value对象一起调用的可选谓词自变量，则仅包括谓词返回真值的成员。

Note

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__().当参数是类并且这些属性已在元类的自定义__dir__()中列出时，getmembers()将仅返回元类中定义的类属性。

inspect.getmodulename(path)

Return the name of the module named by the file path, without including the names of enclosing packages. 返回由文件路径命名的模块的名称，不包括封装包的名称。The file extension is checked against all of the entries in importlib.machinery.all_suffixes(). 将根据importlib.machinery.all_suffixes()中的所有条目检查文件扩展名。If it matches, the final path component is returned with the extension removed. Otherwise, None is returned.如果匹配，则返回最终路径组件，并删除扩展名。否则，将返回None。

Note that this function only returns a meaningful name for actual Python modules - paths that potentially refer to Python packages will still return None.请注意，此函数只为实际的Python模块返回一个有意义的名称——可能引用Python包的路径仍将返回None。

Changed in version 3.3:版本3.3中更改： The function is based directly on importlib.该函数直接基于importlib。

inspect.ismodule(object)

Return True if the object is a module.如果对象是模块，则返回True。

inspect.isclass(object)

Return True if the object is a class, whether built-in or created in Python code.如果对象是类（无论是内置的还是在Python代码中创建的），则返回True。

inspect.ismethod(object)

Return True if the object is a bound method written in Python.如果对象是用Python编写的绑定方法，则返回True。

inspect.isfunction(object)

Return True if the object is a Python function, which includes functions created by a lambda expression.如果对象是Python函数，其中包括由lambda表达式创建的函数，则返回True。

inspect.isgeneratorfunction(object)

Return True if the object is a Python generator function.如果对象是Python生成器函数，则返回True。

Changed in version 3.8:版本3.8中更改： Functions wrapped in functools.partial() now return True if the wrapped function is a Python generator function.如果封装的函数是Python生成器函数，则封装在functools.partial()中的函数现在返回True。

inspect.isgenerator(object)

Return True if the object is a generator.如果对象是生成器，则返回True。

inspect.iscoroutinefunction(object)

Return True if the object is a coroutine function (a function defined with an async def syntax).

New in version 3.5.版本3.5中新增。

Changed in version 3.8:版本3.8中更改： Functions wrapped in functools.partial() now return True if the wrapped function is a coroutine function.

inspect.iscoroutine(object)

Return True if the object is a coroutine created by an async def function.如果对象是由 async def函数创建的协程，则返回True。

New in version 3.5.版本3.5中新增。

inspect.isawaitable(object)

Return True if the object can be used in await expression.

Can also be used to distinguish generator-based coroutines from regular generators:也可用于区分基于生成器的协同程序与常规生成器：

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

New in version 3.5.版本3.5中新增。

inspect.isasyncgenfunction(object)

Return True if the object is an asynchronous generator function, for example:

>>> async def agen():
...     yield 1
...
>>> inspect.isasyncgenfunction(agen)
True

New in version 3.6.版本3.6中新增。

Changed in version 3.8:版本3.8中更改： Functions wrapped in functools.partial() now return True if the wrapped function is a asynchronous generator function.

inspect.isasyncgen(object)

Return True if the object is an asynchronous generator iterator created by an asynchronous generator function.

New in version 3.6.版本3.6中新增。

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 a __set__ or a __delete__ 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 implementation detail: 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 implementation detail: Member descriptors are attributes defined in extension modules via PyMemberDef structures. For Python implementations without such types, this method will always return False.

Retrieving source code

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.

Changed in version 3.5:版本3.5中更改： 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.

Changed in version 3.3:版本3.3中更改： 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.

Changed in version 3.3:版本3.3中更改： 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.清除文档字符串中的缩进，这些缩进与代码块对齐。

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.从第一行中删除所有前导空格。从第二行开始可以一致性删除的任何前导空格都将被删除。开始和结束处的空行随后被删除。此外，所有选项卡都将展开为空格。

Introspecting callables with the Signature object使用Signature对象检查可调用程序

New in version 3.3.版本3.3中新增。

The Signature object represents the call signature of a callable object and its return annotation. To retrieve a Signature object, use the signature() function.Signature对象表示可调用对象的调用签名及其返回注释。要检索Signature对象，请使用signature()函数。

inspect.signature(callable, *, follow_wrapped=True, globals=None, locals=None, eval_str=False)

Return a Signature object for the given callable:返回给定callable的Signature对象：

>>> 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() objects.

For objects defined in modules using stringized annotations (from __future__ import annotations), signature() will attempt to automatically un-stringize the annotations using inspect.get_annotations(). The global, locals, and eval_str parameters are passed into inspect.get_annotations() when resolving the annotations; see the documentation for inspect.get_annotations() for instructions on how to use these parameters.

Raises ValueError if no signature can be provided, and TypeError if that type of object is not supported. Also, if the annotations are stringized, and eval_str is not false, the eval() call(s) to un-stringize the annotations could potentially raise any kind of exception.

A slash(/) in the signature of a function denotes that the parameters prior to it are positional-only. For more info, see the FAQ entry on positional-only parameters.

New in version 3.5.版本3.5中新增。follow_wrapped parameter. Pass False to get a signature of callable specifically (callable.__wrapped__ will not be used to unwrap decorated callables.)

New in version 3.10.版本3.10中新增。globals, locals, and eval_str parameters.

Note

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.某些可调用程序在Python的某些实现中可能不可内省。例如，在CPython中，C中定义的一些内置函数不提供有关其参数的元数据。

classinspect.Signature(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.

The optional parameters 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.

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

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

Changed in version 3.5:版本3.5中更改： Signature objects are picklable and hashable.

empty

A special class-level marker to specify absence of a return annotation.一种特殊的类级标记，用于指定不存在返回注释。

parameters

An ordered mapping of parameters’ names to the corresponding Parameter objects. Parameters appear in strict definition order, including keyword-only parameters.

Changed in version 3.7:版本3.7中更改： Python only explicitly guaranteed that it preserved the declaration order of keyword-only parameters as of version 3.7, although in practice this order had always been preserved in Python 3.Python仅明确保证在3.7版本中保留仅关键字参数的声明顺序，尽管在实践中，Python 3中始终保留此顺序。

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'"
classmethodfrom_callable(obj, *, follow_wrapped=True, globalns=None, localns=None)

Return a 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. globalns and localns will be used as the namespaces when resolving annotations.

This method simplifies subclassing of Signature:

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

New in version 3.5.版本3.5中新增。

New in version 3.10.版本3.10中新增。globalns and localns parameters.

classinspect.Parameter(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.

Changed in version 3.5:版本3.5中更改： Parameter objects are picklable and hashable.参数对象是可拾取和可散列的。

empty

A special class-level marker to specify absence of default values and annotations.一种特殊的类级标记，用于指定不存在默认值和注释。

name

The name of the parameter as a string. The name must be a valid Python identifier.字符串形式的参数名称。该名称必须是有效的Python标识符。

CPython implementation detail: CPython generates implicit parameter names of the form .0 on the code objects used to implement comprehensions and generator expressions.CPython在用于实现理解和生成器表达式的代码对象上生成形式为.0的隐式参数名称。

Changed in version 3.6:版本3.6中更改： These parameter names are exposed by this module as names like implicit0.这些参数名称由该模块公开为类似implicit0的名称。

default

The default value for the parameter. If the parameter has no default value, this attribute is set to Parameter.empty.参数的默认值。如果参数没有默认值，则此属性将设置为Parameter.empty。

annotation

The annotation for the parameter. If the parameter has no annotation, this attribute is set to Parameter.empty.参数的注释。如果参数没有注释，则此属性设置为Parameter.empty。

kind

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

Name

Meaning

POSITIONAL_ONLY

Value must be supplied as a positional argument. Positional only parameters are those which appear before a / entry (if present) in a Python function definition.

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 definition.

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
kind.description

Describes a enum value of Parameter.kind.

New in version 3.8.版本3.8中新增。

Example: print all descriptions of arguments:示例：打印参数的所有描述：

>>> def foo(a, b, *, c, d=10):
...     pass
>>> sig = signature(foo)
>>> for param in sig.parameters.values():
...     print(param.kind.description)
positional or keyword
positional or keyword
keyword-only
keyword-only
replace(*[, name][, kind][, default][, annotation])

Create a new Parameter instance based on the instance replaced was invoked on. 基于调用替换的实例创建新的Parameter实例。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'"

Changed in version 3.4:版本3.4中更改： In Python 3.3 Parameter objects were allowed to have name set to None if their kind was set to POSITIONAL_ONLY. This is no longer permitted.

classinspect.BoundArguments

Result of a Signature.bind() or Signature.bind_partial() call. Holds the mapping of arguments to the function’s parameters.保持参数到函数参数的映射。

arguments

A mutable mapping 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.

Note

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.

Changed in version 3.9:版本3.9中更改： arguments is now of type dict. Formerly, it was of type collections.OrderedDict.

args

A tuple of positional arguments values. Dynamically computed from the arguments attribute.

kwargs

A dict of keyword arguments values. Dynamically computed from the arguments attribute.

signature

A reference to the parent Signature object.

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
{'a': 'spam', 'b': 'ham', 'args': ()}

New in version 3.5.版本3.5中新增。

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)

See also

PEP 362 - Function Signature Object.

The detailed specification, implementation details and examples.

Classes and functions

inspect.getclasstree(classes, 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 parameters. A named tuple ArgSpec(args, varargs, keywords, defaults) is returned. args is a list of the parameter names. varargs and keywords are the names of the * and ** parameters 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: Use getfullargspec() for an updated API that is usually a drop-in replacement, but also correctly handles function annotations and keyword-only parameters.

Alternatively, use signature() and Signature Object, which provide a more structured introspection API for callables.

inspect.getfullargspec(func)

Get the names and default values of a Python function’s parameters. 获取Python函数参数的名称和默认值。A named tuple is returned:返回一个命名元组：

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

args is a list of the positional parameter names. varargs is the name of the * parameter or None if arbitrary positional arguments are not accepted. varkw is the name of the ** parameter or None if arbitrary keyword arguments are not accepted. defaults is an n-tuple of default argument values corresponding to the last n positional parameters, or None if there are no such defaults defined. kwonlyargs is a list of keyword-only parameter names in declaration order. kwonlydefaults is a dictionary mapping parameter names from kwonlyargs to the default values used if no argument is supplied. annotations is a dictionary mapping parameter names to annotations. The special key "return" is used to report the function return value annotation (if any).

Note that signature() and Signature Object provide the recommended API for callable introspection, and support additional behaviours (like positional-only arguments) that are sometimes encountered in extension module APIs. This function is retained primarily for use in code that needs to maintain compatibility with the Python 2 inspect module API.

Changed in version 3.4:版本3.4中更改： 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.

Changed in version 3.6:版本3.6中更改： This method was previously documented as deprecated in favour of signature() in Python 3.5, but that decision has been reversed in order to restore a clearly supported standard interface for single-source Python 2/3 code migrating away from the legacy getargspec() API.

Changed in version 3.7:版本3.7中更改： Python only explicitly guaranteed that it preserved the declaration order of keyword-only parameters as of version 3.7, although in practice this order had always been preserved in Python 3.

inspect.getargvalues(frame)

Get information about arguments passed into a particular frame. A named tuple ArgInfo(args, varargs, keywords, locals) is returned. 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.

Note

This function was inadvertently marked as deprecated in Python 3.5.此函数在Python 3.5中被无意标记为不推荐使用。

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 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.其他六个参数是用于将参数名称、*参数名称、**参数名称、默认值、返回注释和单个注释分别转换为字符串的函数。

For example:

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

Deprecated since version 3.5: Use 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.format*参数是相应的可选格式化函数，用于将名称和值转换为字符串。

Note

This function was inadvertently marked as deprecated in Python 3.5.此函数在Python 3.5中被无意标记为不推荐使用。

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.按方法解析顺序返回类cls的基类（包括cls）的元组。没有类在此元组中出现多次。请注意，方法解析顺序取决于cls的类型。除非使用非常特殊的用户定义元类型，否则cls将是元组的第一个元素。

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'

New in version 3.2.版本3.2中新增。

Deprecated since version 3.5: Use Signature.bind() and Signature.bind_partial() instead.

inspect.getclosurevars(func)

Get the mapping of external name references in a Python function or method func to their current values. A named tuple ClosureVars(nonlocals, globals, builtins, unbound) is returned. 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 is raised if func is not a Python function or method.

New in version 3.3.版本3.3中新增。

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.

New in version 3.4.版本3.4中新增。

inspect.get_annotations(obj, *, globals=None, locals=None, eval_str=False)

Compute the annotations dict for an object.

obj may be a callable, class, or module. Passing in an object of any other type raises TypeError.

Returns a dict. get_annotations() returns a new dict every time it’s called; calling it twice on the same object will return two different but equivalent dicts.返回一个dict.get_annotations()每次调用时都会返回一个新的dict；在同一个对象上调用它两次将返回两个不同但等效的dict。

This function handles several details for you:此函数为您处理以下几个细节：

  • If eval_str is true, values of type str will be un-stringized using eval(). This is intended for use with stringized annotations (from __future__ import annotations).

  • If obj doesn’t have an annotations dict, returns an empty dict. (Functions and methods always have an annotations dict; classes, modules, and other types of callables may not.)

  • Ignores inherited annotations on classes. If a class doesn’t have its own annotations dict, returns an empty dict.

  • All accesses to object members and dict values are done using getattr() and dict.get() for safety.为了安全起见，所有对对象成员和dict值的访问都是使用getattr()和dict.get()完成的。

  • Always, always, always returns a freshly-created dict.总是，总是，总是返回一个新创建的dict。

eval_str controls whether or not values of type str are replaced with the result of calling eval() on those values:

  • If eval_str is true, eval() is called on values of type str. (Note that get_annotations doesn’t catch exceptions; if eval() raises an exception, it will unwind the stack past the get_annotations call.)

  • If eval_str is false (the default), values of type str are unchanged.

globals and locals are passed in to eval(); see the documentation for eval() for more information. If globals or locals is None, this function may replace that value with a context-specific default, contingent on type(obj):

  • If obj is a module, globals defaults to obj.__dict__.

  • If obj is a class, globals defaults to sys.modules[obj.__module__].__dict__ and locals defaults to the obj class namespace.

  • If obj is a callable, globals defaults to obj.__globals__, although if obj is a wrapped function (using functools.update_wrapper()) it is first unwrapped.

Calling get_annotations is best practice for accessing the annotations dict of any object. See Annotations Best Practices for more information on annotations best practices.

New in version 3.10.版本3.10中新增。

The interpreter stack

When the following functions return “frame records,” each record is a named tuple 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.

Changed in version 3.5:版本3.5中更改： Return a named tuple instead of a tuple.

Note

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. 保留对框架对象的引用（如这些函数返回的框架记录的第一个元素中所示）可能会导致程序创建引用循环。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. 一旦创建了引用循环，即使启用了Python的可选循环检测器，也可以从形成循环的对象访问的所有对象的寿命会变得更长。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.如果必须创建这样的循环，重要的是要确保它们被明确地破坏，以避免对象的延迟破坏和内存消耗的增加。

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(). For example:

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() method.

The optional 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 named tuple Traceback(filename, lineno, function, code_context, index) is returned.

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.

Changed in version 3.5:版本3.5中更改： A list of named tuples FrameInfo(frame, filename, lineno, function, code_context, index) is returned.

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.

Changed in version 3.5:版本3.5中更改： A list of named tuples FrameInfo(frame, filename, lineno, function, code_context, index) is returned.

inspect.currentframe()

Return the frame object for the caller’s stack frame.

CPython implementation detail: 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.返回调用方堆栈的帧记录列表。返回列表中的第一个条目表示调用者；最后一个条目表示堆栈上最外层的调用。

Changed in version 3.5:版本3.5中更改： A list of named tuples FrameInfo(frame, filename, lineno, function, code_context, index) is returned.

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.返回当前帧和引发当前正在处理的异常的帧之间的堆栈的帧记录列表。列表中的第一个条目表示调用方；最后一个条目表示引发异常的位置。

Changed in version 3.5:版本3.5中更改： A list of named tuples FrameInfo(frame, filename, lineno, function, code_context, index) is returned.

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__().通过描述符协议__getattr__()或__getattribute__()在不触发动态查找的情况下检索属性。

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.注意：此函数可能无法检索getattr可以获取的所有属性（如动态创建的属性），并且可能会找到getattr无法获取的属性（如引发AttributeError的描述符）。它还可以返回描述符对象，而不是实例成员。

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

New in version 3.2.版本3.2中新增。

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.不解析描述符，例如在C中实现的对象上的槽描述符或getset描述符。返回的是描述符对象，而不是底层属性。

You can handle these with code like the following. Note that for arbitrary getset descriptors invoking these may trigger code execution:您可以使用如下代码来处理这些问题。请注意，对于任意getset描述符，调用这些描述符可能会触发代码执行：

# 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

Current State of Generators and Coroutines发电机的现状及其推论

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. 在实现协程调度器和用于生成器的其他高级用途时，确定生成器当前是否正在执行、是否正在等待启动、恢复或执行，或者是否已经终止是很有用的。getgeneratorstate() allows the current state of a generator to be determined easily.允许容易地确定发电机的当前状态。

inspect.getgeneratorstate(generator)

Get current state of a generator-iterator.

Possible states are:

  • GEN_CREATED: Waiting to start execution.：正在等待开始执行。

  • GEN_RUNNING: Currently being executed by the interpreter.：当前由解释器执行。

  • GEN_SUSPENDED: Currently suspended at a yield expression.：当前在屈服表达式处挂起。

  • GEN_CLOSED: Execution has completed.：执行已完成。

New in version 3.2.版本3.2中新增。

inspect.getcoroutinestate(coroutine)

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 attributes.

Possible states are:

  • CORO_CREATED: Waiting to start execution.：正在等待开始执行。

  • CORO_RUNNING: Currently being executed by the interpreter.：当前由解释器执行。

  • CORO_SUSPENDED: Currently suspended at an await expression.：当前在等待表达式中暂停。

  • CORO_CLOSED: Execution has completed.：执行已完成。

New in version 3.5.版本3.5中新增。

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.

If generator is a generator with no currently associated frame, then an empty dictionary is returned. TypeError is raised if generator is not a Python generator object.

CPython implementation detail:CPython实施细节： 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. 这个函数依赖于生成器公开一个Python堆栈帧进行内省，但不能保证所有Python实现都是这样。In such cases, this function will always return an empty dictionary.在这种情况下，此函数将始终返回一个空字典。

New in version 3.3.版本3.3中新增。

inspect.getcoroutinelocals(coroutine)

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

New in version 3.5.版本3.5中新增。

Code Objects Bit Flags

Python code objects have a co_flags attribute, which is a bitmap of the following flags:Python代码对象具有co_flags属性，该属性是以下标志的位图：

inspect.CO_OPTIMIZED

The code object is optimized, using fast locals.使用快速局部变量对代码对象进行了优化。

inspect.CO_NEWLOCALS

If set, a new dict will be created for the frame’s f_locals when the code object is executed.如果设置，则在执行代码对象时，将为帧的f_locals创建一个新的dict。

inspect.CO_VARARGS

The code object has a variable positional parameter (*args-like).代码对象有一个可变的位置参数（类似于*args）。

inspect.CO_VARKEYWORDS

The code object has a variable keyword parameter (**kwargs-like).

inspect.CO_NESTED

The flag is set when the code object is a nested function.当代码对象是嵌套函数时，将设置该标志。

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.当代码对象是生成器函数时设置该标志，即当代码对象执行时返回生成器对象。

inspect.CO_NOFREE

The flag is set if there are no free or cell variables.如果没有空闲变量或单元格变量，则会设置该标志。

inspect.CO_COROUTINE

The flag is set when the code object is a coroutine function. When the code object is executed it returns a coroutine object. 当代码对象是协程函数时，会设置该标志。当代码对象被执行时，它返回一个协程对象。See PEP 492 for more details.

New in version 3.5.版本3.5中新增。

inspect.CO_ITERABLE_COROUTINE

The flag is used to transform generators into generator-based coroutines. 该标志用于将生成器转换为基于生成器的协同程序。Generator objects with this flag can be used in await expression, and can yield from coroutine objects. See PEP 492 for more details.

New in version 3.5.版本3.5中新增。

inspect.CO_ASYNC_GENERATOR

The flag is set when the code object is an asynchronous generator function. When the code object is executed it returns an asynchronous generator object. 当代码对象是异步生成器函数时，将设置该标志。当代码对象被执行时，它返回一个异步生成器对象。See PEP 525 for more details.详见PEP 525。

New in version 3.6.版本3.6中新增。

Note

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. 这些标志是特定于CPython的，可能不会在其他Python实现中定义。此外，这些标志是一个实现细节，可以在未来的Python版本中删除或弃用。It’s recommended to use public APIs from the inspect module for any introspection needs.对于任何内省需求，建议使用inspect模块中的公共API。

Command Line Interface命令行接口

The inspect module also provides a basic introspection capability from the command line.inspect模块还通过命令行提供基本的自检功能。

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.默认情况下，接受模块的名称并打印该模块的源代码。模块中的类或函数可以通过附加冒号和目标对象的限定名来打印。

--details

Print information about the specified object rather than the source code打印有关指定对象的信息，而不是源代码