ubelt.util_import module

Expose functions to simplify importing from module names and paths.

The ubelt.import_module_from_path() function does its best to load a python file into th current set of global modules.

The ubelt.import_module_from_name() works similarly.

The ubelt.modname_to_modpath() and ubelt.modname_to_modpath() work statically and convert between module names and file paths on disk.

The ubelt.split_modpath() function separates modules into a root and base path depending on where the first __init__.py file is.

ubelt.util_import.split_modpath(modpath, check=True)[source]

Splits the modpath into the dir that must be in PYTHONPATH for the module to be imported and the modulepath relative to this directory.

  • modpath (str) – module filepath

  • check (bool) – if False, does not raise an error if modpath is a directory and does not contain an __init__.py file.


(directory, rel_modpath)

Return type

Tuple[str, str]


ValueError – if modpath does not exist or is not a package


>>> from xdoctest import static_analysis
>>> modpath = static_analysis.__file__.replace('.pyc', '.py')
>>> modpath = abspath(modpath)
>>> dpath, rel_modpath = split_modpath(modpath)
>>> recon = join(dpath, rel_modpath)
>>> assert recon == modpath
>>> assert rel_modpath == join('xdoctest', 'static_analysis.py')
ubelt.util_import.modname_to_modpath(modname, hide_init=True, hide_main=False, sys_path=None)[source]

Finds the path to a python module from its name.

Determines the path to a python module without directly import it

Converts the name of a module (__name__) to the path (__file__) where it is located without importing the module. Returns None if the module does not exist.

  • modname (str) – The name of a module in sys_path.

  • hide_init (bool) – if False, __init__.py will be returned for packages. Defaults to True.

  • hide_main (bool) – if False, and hide_init is True, __main__.py will be returned for packages, if it exists. Defautls to False.

  • sys_path (None | List[str | PathLike]) – The paths to search for the module. If unspecified, defaults to sys.path.


modpath - path to the module, or None if it doesn’t exist

Return type

str | None


>>> modname = 'xdoctest.__main__'
>>> modpath = modname_to_modpath(modname, hide_main=False)
>>> assert modpath.endswith('__main__.py')
>>> modname = 'xdoctest'
>>> modpath = modname_to_modpath(modname, hide_init=False)
>>> assert modpath.endswith('__init__.py')
>>> # xdoctest: +REQUIRES(CPython)
>>> modpath = basename(modname_to_modpath('_ctypes'))
>>> assert 'ctypes' in modpath
ubelt.util_import.modpath_to_modname(modpath, hide_init=True, hide_main=False, check=True, relativeto=None)[source]

Determines importable name from file path

Converts the path to a module (__file__) to the importable python name (__name__) without importing the module.

The filename is converted to a module name, and parent directories are recursively included until a directory without an __init__.py file is encountered.

  • modpath (str) – module filepath

  • hide_init (bool, default=True) – removes the __init__ suffix

  • hide_main (bool, default=False) – removes the __main__ suffix

  • check (bool, default=True) – if False, does not raise an error if modpath is a dir and does not contain an __init__ file.

  • relativeto (str | None, default=None) – if specified, all checks are ignored and this is considered the path to the root module.




Return type



ValueError – if check is True and the path does not exist


>>> from xdoctest import static_analysis
>>> modpath = static_analysis.__file__.replace('.pyc', '.py')
>>> modpath = modpath.replace('.pyc', '.py')
>>> modname = modpath_to_modname(modpath)
>>> assert modname == 'xdoctest.static_analysis'


>>> import xdoctest
>>> assert modpath_to_modname(xdoctest.__file__.replace('.pyc', '.py')) == 'xdoctest'
>>> assert modpath_to_modname(dirname(xdoctest.__file__.replace('.pyc', '.py'))) == 'xdoctest'


>>> # xdoctest: +REQUIRES(CPython)
>>> modpath = modname_to_modpath('_ctypes')
>>> modname = modpath_to_modname(modpath)
>>> assert modname == '_ctypes'


>>> modpath = '/foo/libfoobar.linux-x86_64-3.6.so'
>>> modname = modpath_to_modname(modpath, check=False)
>>> assert modname == 'libfoobar'

Imports a module from its string name (i.e. __name__)

This is a simple wrapper around importlib.import_module(), but is provided as a companion function to import_module_from_path(), which contains functionality not provided in the Python standard library.


modname (str) – module name



Return type





>>> # test with modules that won't be imported in normal circumstances
>>> # todo write a test where we guarantee this
>>> modname_list = [
>>>     'pickletools',
>>>     'lib2to3.fixes.fix_apply',
>>> ]
>>> #assert not any(m in sys.modules for m in modname_list)
>>> modules = [import_module_from_name(modname) for modname in modname_list]
>>> assert [m.__name__ for m in modules] == modname_list
>>> assert all(m in sys.modules for m in modname_list)
ubelt.util_import.import_module_from_path(modpath, index=-1)[source]

Imports a module via a filesystem path.

This works by modifying sys.path, importing the module name, and then attempting to undo the change to sys.path. This function may produce unexpected results in the case where the imported module itself itself modifies sys.path or if there is another conflicting module with the same name.

  • modpath (str | PathLike) – Path to the module on disk or within a zipfile. Paths within a zipfile can be given by <path-to>.zip/<path-inside-zip>.py.

  • index (int) – Location at which we modify PYTHONPATH if necessary. If your module name does not conflict, the safest value is -1, However, if there is a conflict, then use an index of 0. The default may change to 0 in the future.


the imported module

Return type





  • IOError - when the path to the module does not exist

  • ImportError - when the module is unable to be imported


If the module is part of a package, the package will be imported first. These modules may cause problems when reloading via IPython magic

This can import a module from within a zipfile. To do this modpath should specify the path to the zipfile and the path to the module within that zipfile separated by a colon or pathsep. E.g. “/path/to/archive.zip:mymodule.pl”


It is best to use this with paths that will not conflict with previously existing modules.

If the modpath conflicts with a previously existing module name. And the target module does imports of its own relative to this conflicting path. In this case, the module that was loaded first will win.

For example if you try to import ‘/foo/bar/pkg/mod.py’ from the folder structure:

- foo/
  +- bar/
     +- pkg/
        +  __init__.py
        |- mod.py
        |- helper.py

If there exists another module named pkg already in sys.modules and mod.py does something like from . import helper, Python will assume helper belongs to the pkg module already in sys.modules. This can cause a NameError or worse — a incorrect helper module.




>>> import xdoctest
>>> modpath = xdoctest.__file__
>>> module = import_module_from_path(modpath)
>>> assert module is xdoctest


>>> # Test importing a module from within a zipfile
>>> import zipfile
>>> from xdoctest import utils
>>> from os.path import join, expanduser, normpath
>>> dpath = expanduser('~/.cache/xdoctest')
>>> dpath = utils.ensuredir(dpath)
>>> #dpath = utils.TempDir().ensure()
>>> # Write to an external module named bar
>>> external_modpath = join(dpath, 'bar.py')
>>> # For pypy support we have to write this using with
>>> with open(external_modpath, 'w') as file:
>>>     file.write('testvar = 1')
>>> internal = 'folder/bar.py'
>>> # Move the external bar module into a zipfile
>>> zippath = join(dpath, 'myzip.zip')
>>> with zipfile.ZipFile(zippath, 'w') as myzip:
>>>     myzip.write(external_modpath, internal)
>>> # Import the bar module from within the zipfile
>>> modpath = zippath + ':' + internal
>>> modpath = zippath + os.path.sep + internal
>>> module = import_module_from_path(modpath)
>>> assert normpath(module.__name__) == normpath('folder/bar')
>>> assert module.testvar == 1


>>> import pytest
>>> with pytest.raises(IOError):
>>>     import_module_from_path('does-not-exist')
>>> with pytest.raises(IOError):
>>>     import_module_from_path('does-not-exist.zip/')