31.7. runpy
— Locating and executing Python modules¶
2.5 新版功能.
Source code: Lib/runpy.py
The 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.
The runpy
module provides two functions:
-
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.
If the supplied 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__
,__file__
,__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__
is set to run_name if this optional argument is notNone
, tomod_name + '.__main__'
if the named module is a package and to the mod_name argument otherwise.__file__
is set to the name provided by the module loader. If the loader does not make filename information available, this variable is set toNone
.__loader__
is set to the PEP 302 module loader used to retrieve the code for the module (This loader may be a wrapper around the standard import mechanism).__package__
is set to mod_name if the named module is a package and tomod_name.rpartition('.')[0]
otherwise.If the argument alter_sys is supplied and evaluates to
True
, thensys.argv[0]
is updated with the value of__file__
andsys.modules[__name__]
is updated with a temporary module object for the module being executed. Bothsys.argv[0]
andsys.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 thesys
module be left alone when invoking this function from threaded code.参见
The
-m
option offering equivalent functionality from the command line.在 2.7 版更改: Added ability to execute packages by looking for a
__main__
submodule
-
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 onsys.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__
,__file__
,__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__
is set to run_name if this optional argument is notNone
and to'<run_path>'
otherwise.__file__
is set to the name provided by the module loader. If the loader does not make filename information available, this variable is set toNone
. For a simple script, this will be set tofile_path
.__loader__
is set to the PEP 302 module loader used to retrieve the code for the module (This loader may be a wrapper around the standard import mechanism). For a simple script, this will be set toNone
.__package__
is set to__name__.rpartition('.')[0]
.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 offile_path
andsys.modules[__name__]
is updated with a temporary module object for the module being executed. All modifications to items insys
are reverted before the function returns.Note that, unlike
run_module()
, the alterations made tosys
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.参见
接口选项 for equivalent functionality on the command line (
python path/to/script
).2.7 新版功能.