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Title: inspect — Inspect live objects — Python 3.13.18 documentation
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Venue: pydoc
Year: 2001
Canonical: pydoc:inspect@3.13
URL: https://docs.python.org/3.13/library/inspect.html
Collector: pydoc
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ABSTRACT
inspect — Inspect live objects — Python 3.13.18 documentation Navigation index modules | next | previous | Python » 3.13.18 Documentation » The Python standard library » Python Runtime Services » inspect — Inspect live objects | Theme Auto Light Dark | inspect — Inspect live objects¶ 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. 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. 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. Types and members¶ The getmembers() function retrieves the members of an object such as a class or module. The functions whose names begin with “is” are mainly provided as convenient choices for the second argument to getmembers(). They also help you determine when you can expect to find the following special attributes (see Import-related attributes on module objects for module attributes): Type Attribute Description class __doc__ documentation string __name__ name with which this class was defined __qualname__ qualified name __module__ name of module in which this class was defined __type_params__ A tuple containing the type parameters of a generic class method __doc__ documentation string __name__ name with which this method was defined __qualname__ qualified name __func__ function object containing implementation of method __self__ instance to which this method is bound, or None __module__ name of module in which this method was defined function __doc__ documentation string __name__ name with which this function was defined __qualname__ qualified name __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 parameters __globals__ global namespace in which this function was defined __builtins__ builtins namespace __annotations__ mapping of parameters names to annotations; "return" key is reserved for return annotations. __type_params__ A tuple containing the type parameters of a generic function __module__ name of module in which this function was defined 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_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_posonlyargcount number of positional only arguments co_kwonlyargcount number of keyword only arguments (not including ** arg) co_name name with which this code object was defined co_qualname fully qualified name with which this code object was defined co_names tuple of names other than arguments and function locals 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__ name __qualname__ qualified name gi_frame frame gi_running is the generator running? gi_suspended is the generator suspended? gi_code code gi_yieldfrom object being iterated by yield from, or None async generator __name__ name __qualname__ qualified name ag_await object being awaited on, or None ag_frame frame ag_running is the generator running? ag_suspended is the generator suspended? ag_code code coroutine __name__ name __qualname__ qualified name cr_await object being awaited on, or None cr_frame frame cr_running is the coroutine running? cr_suspended is the coroutine suspended? cr_code code cr_origin where coroutine was created, or None. See sys.set_coroutine_origin_tracking_depth() builtin __doc__ documentation string __name__ original name of this function or method __qualname__ qualified name __self__ instance to which a method is bound, or None Changed in version 3.5: Add __qualname__ and gi_yieldfrom attributes to generators. The __name__ attribute of generators is now set from the function name, instead of the code name, and it can now be modified. Changed in version 3.7: Add cr_origin attribute to coroutines. Changed in version 3.10: Add __builtins__ attribute to functions. Changed in version 3.11: Add gi_suspended attribute to generators. Changed in version 3.11: Add cr_suspended attribute to coroutines. Changed in version 3.12: Add ag_suspended attribute to async generators. 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—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. 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__(). inspect.getmembers_static(object[, predicate])¶ Return all the members of an object in a list of (name, value) pairs sorted by name without triggering dynamic lookup via the descriptor protocol, __getattr__ or __getattribute__. Optionally, only return members that satisfy a given predicate. Note getmembers_static() may not be able to retrieve all members that getmembers can fetch (like dynamically created attributes) and may find members that getmembers can’t (like descriptors that raise AttributeError). It can also return descriptor objects instead of instance members in some cases. Added in version 3.11. 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 is returned. Note that this function only returns a meaningful name for actual Python modules - paths that potentially refer to Python packages will still return None. Changed in version 3.3: The function is based directly on importlib. 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. This function returns False for generic aliases of classes, such as list[int]. 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 expression. inspect.isgeneratorfunction(object)¶ Return True if the object is a Python generator function. Changed in version 3.8: Functions wrapped in functools.partial() now return True if the wrapped function is a Python generator function. Changed in version 3.10.6: Duck-typed function-like objects now return True if their code object has the CO_GENERATOR flag. Changed in version 3.13: Functions wrapped in functools.partialmethod() now return True if the wrapped function 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 coroutine function (a function defined with an async def syntax), a functools.partial() wrapping a coroutine function, or a sync function marked with markcoroutinefunction(). Added in version 3.5. Changed in version 3.8: Functions wrapped in functools.partial() now return True if the wrapped function is a coroutine function. Changed in version 3.10.6: Duck-typed function-like objects now return True if their code object has the CO_COROUTINE flag. Changed in version 3.12: Sync functions marked with markcoroutinefunction() now return True. Changed in version 3.13: Functions wrapped in functools.partialmethod() now return True if the wrapped function is a coroutine function. inspect.markcoroutinefunction(func)¶ Decorator to mark a callable as a coroutine function if it would not otherwise be detected by iscoroutinefunction(). This may be of use for sync functions that return a coroutine, if the function is passed to an API that requires iscoroutinefunction(). When possible, using an async def function is preferred. Also acceptable is calling the function and testing the return with iscoroutine(). Added in version 3.12. inspect.iscoroutine(object)¶ Return True if the object is a coroutine created by an async def function. Added in version 3.5. 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: import types def gen(): yield @types.coroutine def gen_coro(): yield assert not isawaitable(gen()) assert isawaitable(gen_coro()) Added in version 3.5. inspect.isasyncgenfunction(object)¶ Return True if the object is an asynchronous generator function, for example: async def agen(): ... yield 1 ... inspect.isasyncgenfunction(agen) True Added in version 3.6. Changed in version 3.8: Functions wrapped in functools.partial() now return True if the wrapped function is an asynchronous generator function. Changed in version 3.10.6: Duck-typed function-like objects now return True if their code object has the CO_ASYNC_GENERATOR flag. Changed in version 3.13: Functions wrapped in functools.partialmethod() 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. Added in version 3.6. 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.ismethodwrapper(object)¶ Return True if the type of object is a MethodWrapperType. These are instances of MethodWrapperType, such as __str__(), __eq__() and __repr__(). Added in version 3.11. 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 isclass(), ismethod() or isfunction() is true. This, for example, is true of int.__add__. An object passing this test has a __get__() method, but not a __set__() method or a __delete__() method. Beyond that, the set of attributes varies. A __name__ attribute is usually sensible, and __doc__ often is. Method descriptors that also pass any of the other tests (isclass(), ismethod() or isfunction()) make this function return False, simply because those other tests promise more – you can, for example, count on having the __func__ attribute when an object passes ismethod(). Changed in version 3.13: This function no longer incorrectly reports objects with __get__() and __delete__(), but not __set__(), as being method descriptors (such objects are data descriptors, not method descriptors). inspect.isdatadescriptor(object)¶ Return True if the object is a data descriptor, but not if isclass(), ismethod() or isfunction() is true. Data descriptors always have a __set__() method and/or a __delete__() method. Optionally, they may also have a __get__() method. Examples of data descriptors are properties, getsets and member descriptors. Note that for the latter two (defined only in C extension modules), more specific tests are available: isgetsetdescriptor() and ismemberdescriptor(), respectively. While data descriptors may also have __name__ and __doc__ attributes (as properties, getsets and member descriptors do), this is not necessarily the case in general. Changed in version 3.8: This function now reports objects with only a __set__() method as being data descriptors (the presence of __get__() is no longer required for that). Moreover, objects with __delete__(), but not __set__(), are now properly recognized as data descriptors as well, which was not the case previously. 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. Return None if the documentation string is invalid or missing. Changed in version 3.5: 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. An OSError is raised if the source code cannot be retrieved. 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. Return None if the module cannot be determined. inspect.getsourcefile(object)¶ Return the name of the Python source file in which an object was defined or None if no way can be identified to get the source. An OSError is raised if the source code cannot be retrieved. 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. A TypeError is raised if the object is a built-in module, class, or function. Changed in version 3.3: 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. A TypeError is raised if the object is a built-in module, class, or function. Changed in version 3.3: 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. Introspecting callables with the Signature object¶ Added in version 3.3. The Signature object represents the call signature of a callable object and its return annotation. To retrieve a Signature object, use the signature() function. inspect.signature(callable, *, follow_wrapped=True, globals=None, locals=None, eval_str=False)¶ Return a Signature object for the given 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 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 get_annotations(). The globals, locals, and eval_str parameters are passed into get_annotations() when resolving the annotations; see the documentation for 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 in get_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. Changed in version 3.5: The follow_wrapped parameter was added. Pass False to get a signature of callable specifically (callable.__wrapped__ will not be used to unwrap decorated callables.) Changed in version 3.10: The globals, locals, and eval_str parameters were added. 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. CPython implementation detail: If the passed object has a __signature__ attribute, we may use it to create the signature. The exact semantics are an implementation detail and are subject to unannounced changes. Consult the source code for current semantics. class inspect.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. It represents the “return” annotation of the callable. Signature objects are immutable. Use Signature.replace() or copy.replace() to make a modified copy. Changed in version 3.5: Signature objects are now picklable and hashable. empty¶ A special class-level marker to specify absence of a return annotation. 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: 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. 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'" Signature objects are also supported by the generic function copy.replace(). format(*, max_width=None)¶ Create a string representation of the Signature object. If max_width is passed, the method will attempt to fit the signature into lines of at most max_width characters. If the signature is longer than max_width, all parameters will be on separate lines. Added in version 3.13. classmethod from_callable(obj, *, follow_wrapped=True, globals=None, locals=None, eval_str=False)¶ Return a Signature (or its subclass) object for a given callable obj. This method simplifies subclassing of Signature: class MySignature(Signature): pass sig = MySignature.from_callable(sum) assert isinstance(sig, MySignature) Its behavior is otherwise identical to that of signature(). Added in version 3.5. Changed in version 3.10: The globals, locals, and eval_str parameters were added. class inspect.Parameter(name, kind, *, default=Parameter.empty, annotation=Parameter.empty)¶ Parameter objects are immutable. Instead of modifying a Parameter object, you can use Parameter.replace() or copy.replace() to create a modified copy. Changed in version 3.5: Parameter objects are now picklable and hashable. empty¶ A special class-level marker to specify absence of default values and annotations. name¶ The name of the parameter as a string. The name must be a valid Python identifier. CPython implementation detail: CPython generates implicit parameter names of the form .0 on the code objects used to implement comprehensions and generator expressions. Changed in version 3.6: These parameter names are now exposed by this module as names like implicit0. 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. The possible values are accessible via Parameter (like Parameter.KEYWORD_ONLY), and support comparison and ordering, in the following order: 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 an enum value of Parameter.kind. Added in version 3.8. Example: print all descriptions of arguments: 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. 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'" Parameter objects are also supported by the generic function copy.replace(). Changed in version 3.4: 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. class inspect.BoundArguments¶ Result of a Signature.bind() or Signature.bind_partial() call. Holds the mapping of arguments to the function’s parameters. 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: 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. Arguments that can be passed positionally are included in args instead. 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': ()} Added in version 3.5. 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.getfullargspec(func)¶ Get the names and default values of a Python function’s parameters. A named tuple is returned: 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: 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: 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: 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. 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. Note 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' Added in version 3.2. 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. Added in version 3.3. 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. Added in version 3.4. 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. This function handles several details for you: 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. Always, always, always returns a freshly created 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. Added in version 3.10. The interpreter stack¶ Some of the following functions return FrameInfo objects. For backwards compatibility these objects allow tuple-like operations on all attributes except positions. This behavior is considered deprecated and may be removed in the future. class inspect.FrameInfo¶ frame¶ The frame object that the record corresponds to. filename¶ The file name associated with the code being executed by the frame this record corresponds to. lineno¶ The line number of the current line associated with the code being executed by the frame this record corresponds to. function¶ The function name that is being executed by the frame this record corresponds to. code_context¶ A list of lines of context from the source code that’s being executed by the frame this record corresponds to. index¶ The index of the current line being executed in the code_context list. positions¶ A dis.Positions object containing the start line number, end line number, start column offset, and end column offset associated with the instruction being executed by the frame this record corresponds to. Changed in version 3.5: Return a named tuple instead of a tuple. Changed in version 3.11: FrameInfo is now a class instance (that is backwards compatible with the previous named tuple). class inspect.Traceback¶ filename¶ The file name associated with the code being executed by the frame this traceback corresponds to. lineno¶ The line number of the current line associated with the code being executed by the frame this traceback corresponds to. function¶ The function name that is being executed by the frame this traceback corresponds to. code_context¶ A list of lines of context from the source code that’s being executed by the frame this traceback corresponds to. index¶ The index of the current line being executed in the code_context list. positions¶ A dis.Positions object containing the start line number, end line number, start column offset, and end column offset associated with the instruction being executed by the frame this traceback corresponds to. Changed in version 3.11: Traceback is now a class instance (that is backwards compatible with the previous named 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. 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(). 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 Traceback object is returned. Changed in version 3.11: A Traceback object is returned instead of a named tuple. inspect.getouterframes(frame, context=1)¶ Get a list of FrameInfo objects 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: A list of named tuples FrameInfo(frame, filename, lineno, function, code_context, index) is returned. Changed in version 3.11: A list of FrameInfo objects is returned. inspect.getinnerframes(traceback, context=1)¶ Get a list of FrameInfo objects 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: A list of named tuples FrameInfo(frame, filename, lineno, function, code_context, index) is returned. Changed in version 3.11: A list of FrameInfo objects 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 FrameInfo objects 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. Changed in version 3.5: A list of named tuples FrameInfo(frame, filename, lineno, function, code_context, index) is returned. Changed in version 3.11: A list of FrameInfo objects is returned. inspect.trace(context=1)¶ Return a list of FrameInfo objects 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. Changed in version 3.5: A list of named tuples FrameInfo(frame, filename, lineno, function, code_context, index) is returned. Changed in version 3.11: A list of FrameInfo objects 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 a similar signature as getattr() but avoids executing code when it fetches attributes. inspect.getattr_static(obj, attr)¶ inspect.getattr_static(obj, attr, default) 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. Added in version 3.2. 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 Current State of Generators, Coroutines, and Asynchronous Generators¶ 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. Added in version 3.2. 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. CORO_RUNNING: Currently being executed by the interpreter. CORO_SUSPENDED: Currently suspended at an await expression. CORO_CLOSED: Execution has completed. Added in version 3.5. inspect.getasyncgenstate(agen)¶ Get current state of an asynchronous generator object. The function is intended to be used with asynchronous iterator objects created by async def functions which use the yield statement, but will accept any asynchronous generator-like object that has ag_running and ag_frame attributes. Possible states are: AGEN_CREATED: Waiting to start execution. AGEN_RUNNING: Currently being executed by the interpreter. AGEN_SUSPENDED: Currently suspended at a yield expression. AGEN_CLOSED: Execution has completed. Added in version 3.12. 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: 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. Added in version 3.3. inspect.getcoroutinelocals(coroutine)¶ This function is analogous to getgeneratorlocals(), but works for coroutine objects created by async def functions. Added in version 3.5. inspect.getasyncgenlocals(agen)¶ This function is analogous to getgeneratorlocals(), but works for asynchronous generator objects created by async def functions which use the yield statement. Added in version 3.12. 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-like). 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. 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_COROUTINE¶ The flag is set when the code object is a coroutine function. When the code object is executed it returns a coroutine object. See PEP 492 for more details. Added in version 3.5. inspect.CO_ITERABLE_COROUTINE¶ The flag is used to transform 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 for more details. Added in version 3.5. 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. See PEP 525 for more details. Added in version 3.6. 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. It’s recommended to use public APIs from the inspect module for any introspection needs. Buffer flags¶ class inspect.BufferFlags¶ This is an enum.IntFlag that represents the flags that can be passed to the __buffer__() method of objects implementing the buffer protocol. The meaning of the flags is explained at Buffer request types. SIMPLE¶ WRITABLE¶ FORMAT¶ ND¶ STRIDES¶ C_CONTIGUOUS¶ F_CONTIGUOUS¶ ANY_CONTIGUOUS¶ INDIRECT¶ CONTIG¶ CONTIG_RO¶ STRIDED¶ STRIDED_RO¶ RECORDS¶ RECORDS_RO¶ FULL¶ FULL_RO¶ READ¶ WRITE¶ Added in version 3.12. 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 Table of Contents inspect — Inspect live objects Types and members Retrieving source code Introspecting callables with the Signature object Classes and functions The interpreter stack Fetching attributes statically Current State of Generators, Coroutines, and Asynchronous Generators Code Objects Bit Flags Buffer flags Command-line interface Previous topic gc — Garbage Collector interface Next topic site — Site-specific configuration hook This page Report a bug Show source « Navigation index modules | next | previous | Python » 3.13.18 Documentation » The Python standard library » Python Runtime Services » inspect — Inspect live objects | Theme Auto Light Dark | © Copyright 2001-2026, Python Software Foundation. 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