runpy
— 定位和执行 Python 模块
¶
源代码： Lib/runpy.py
runpy
module is used to locate and run Python modules without importing them first. Its main use is to implement the
-m
command line switch that allows scripts to be located using the Python module namespace rather than the filesystem.
Note that this is not a sandbox module - all code is executed in the current process, and any side effects (such as cached imports of other modules) will remain in place after the functions have returned.
Furthermore, any functions and classes defined by the executed code are not guaranteed to work correctly after a
runpy
function has returned. If that limitation is not acceptable for a given use case,
importlib
is likely to be a more suitable choice than this module.
runpy
模块提供 2 函数：
runpy.
run_module
(
mod_name
,
init_globals=None
,
run_name=None
,
alter_sys=False
)
¶
Execute the code of the specified module and return the resulting module globals dictionary. The module’s code is first located using the standard import mechanism (refer to PEP 302 for details) and then executed in a fresh module namespace.
mod_name
argument should be an absolute module name. If the module name refers to a package rather than a normal module, then that package is imported and the
__main__
submodule within that package is then executed and the resulting module globals dictionary returned.
The optional dictionary argument
init_globals
may be used to pre-populate the module’s globals dictionary before the code is executed. The supplied dictionary will not be modified. If any of the special global variables below are defined in the supplied dictionary, those definitions are overridden by
run_module()
.
The special global variables
__name__
,
__spec__
,
__file__
,
__cached__
,
__loader__
and
__package__
are set in the globals dictionary before the module code is executed (Note that this is a minimal set of variables - other variables may be set implicitly as an interpreter implementation detail).
__name__
被设为
run_name
if this optional argument is not
None
, to
mod_name
+
'.__main__'
if the named module is a package and to the
mod_name
argument otherwise.
__spec__
will be set appropriately for the
actually
imported module (that is,
__spec__.name
will always be
mod_name
or
mod_name
+
'.__main__
, never
run_name
).
__file__
,
__cached__
,
__loader__
and
__package__
are
set as normal
based on the module spec.
If the argument
alter_sys
is supplied and evaluates to
True
, then
sys.argv[0]
is updated with the value of
__file__
and
sys.modules[__name__]
is updated with a temporary module object for the module being executed. Both
sys.argv[0]
and
sys.modules[__name__]
are restored to their original values before the function returns.
Note that this manipulation of
sys
is not thread-safe. Other threads may see the partially initialised module, as well as the altered list of arguments. It is recommended that the
sys
module be left alone when invoking this function from threaded code.
另请参阅
-m
option offering equivalent functionality from the command line.
3.1 版改变：
Added ability to execute packages by looking for a
__main__
子模块。
3.2 版改变：
添加
__cached__
全局变量 (见
PEP 3147
).
3.4 版改变：
Updated to take advantage of the module spec feature added by
PEP 451
。这允许
__cached__
to be set correctly for modules run this way, as well as ensuring the real module name is always accessible as
__spec__.name
.
runpy.
run_path
(
file_path
,
init_globals=None
,
run_name=None
)
¶
Execute the code at the named filesystem location and return the resulting module globals dictionary. As with a script name supplied to the CPython command line, the supplied path may refer to a Python source file, a compiled bytecode file or a valid sys.path entry containing a
__main__
module (e.g. a zipfile containing a top-level
__main__.py
file).
For a simple script, the specified code is simply executed in a fresh module namespace. For a valid sys.path entry (typically a zipfile or directory), the entry is first added to the beginning of
sys.path
. The function then looks for and executes a
__main__
module using the updated path. Note that there is no special protection against invoking an existing
__main__
entry located elsewhere on
sys.path
if there is no such module at the specified location.
The optional dictionary argument
init_globals
may be used to pre-populate the module’s globals dictionary before the code is executed. The supplied dictionary will not be modified. If any of the special global variables below are defined in the supplied dictionary, those definitions are overridden by
run_path()
.
The special global variables
__name__
,
__spec__
,
__file__
,
__cached__
,
__loader__
and
__package__
are set in the globals dictionary before the module code is executed (Note that this is a minimal set of variables - other variables may be set implicitly as an interpreter implementation detail).
__name__
被设为
run_name
if this optional argument is not
None
and to
'<run_path>'
否则。
If the supplied path directly references a script file (whether as source or as precompiled byte code), then
__file__
will be set to the supplied path, and
__spec__
,
__cached__
,
__loader__
and
__package__
will all be set to
None
.
If the supplied path is a reference to a valid sys.path entry, then
__spec__
will be set appropriately for the imported
__main__
module (that is,
__spec__.name
will always be
__main__
).
__file__
,
__cached__
,
__loader__
and
__package__
将是
set as normal
based on the module spec.
A number of alterations are also made to the
sys
module. Firstly,
sys.path
may be altered as described above.
sys.argv[0]
is updated with the value of
file_path
and
sys.modules[__name__]
is updated with a temporary module object for the module being executed. All modifications to items in
sys
are reverted before the function returns.
Note that, unlike
run_module()
, the alterations made to
sys
are not optional in this function as these adjustments are essential to allowing the execution of sys.path entries. As the thread-safety limitations still apply, use of this function in threaded code should be either serialised with the import lock or delegated to a separate process.
另请参阅
接口选项
for equivalent functionality on the command line (
python
path/to/script
).
3.2 版新增。
3.4 版改变：
Updated to take advantage of the module spec feature added by
PEP 451
。这允许
__cached__
to be set correctly in the case where
__main__
is imported from a valid sys.path entry rather than being executed directly.
另请参阅
命令行和环境 - CPython command line details
importlib.import_module()
function