How to import a module given the full path?

问题

How can I load a Python module given its full path? Note that the file can be anywhere in the filesystem, as it is a configuration option.

回答1:

For Python 3.5+ use:

import importlib.util
spec = importlib.util.spec_from_file_location("module.name", "/path/to/file.py")
foo = importlib.util.module_from_spec(spec)
spec.loader.exec_module(foo)
foo.MyClass()

For Python 3.3 and 3.4 use:

from importlib.machinery import SourceFileLoader

foo = SourceFileLoader("module.name", "/path/to/file.py").load_module()
foo.MyClass()

(Although this has been deprecated in Python 3.4.)

For Python 2 use:

import imp

foo = imp.load_source('module.name', '/path/to/file.py')
foo.MyClass()

There are equivalent convenience functions for compiled Python files and DLLs.

See also http://bugs.python.org/issue21436.

回答2:

The advantage of adding a path to sys.path (over using imp) is that it simplifies things when importing more than one module from a single package. For example:

import sys
# the mock-0.3.1 dir contains testcase.py, testutils.py & mock.py
sys.path.append('/foo/bar/mock-0.3.1')

from testcase import TestCase
from testutils import RunTests
from mock import Mock, sentinel, patch

回答3:

To import your module, you need to add its directory to the environment variable, either temporarily or permanently.

Temporarily

import sys
sys.path.append("/path/to/my/modules/")
import my_module

Permanently

Adding the following line to your .bashrc file (in linux) and excecute source ~/.bashrc in the terminal:

export PYTHONPATH="${PYTHONPATH}:/path/to/my/modules/"

Credit/Source: saarrrr, another stackexchange question

回答4:

If your top-level module is not a file but is packaged as a directory with __init__.py, then the accepted solution almost works, but not quite. In Python 3.5+ the following code is needed (note the added line that begins with 'sys.modules'):

MODULE_PATH = "/path/to/your/module/__init__.py"
MODULE_NAME = "mymodule"
import importlib
import sys
spec = importlib.util.spec_from_file_location(MODULE_NAME, MODULE_PATH)
module = importlib.util.module_from_spec(spec)
sys.modules[spec.name] = module 
spec.loader.exec_module(module)

Without this line, when exec_module is executed, it tries to bind relative imports in your top level __init__.py to the top level module name -- in this case "mymodule". But "mymodule" isn't loaded yet so you'll get the error "SystemError: Parent module 'mymodule' not loaded, cannot perform relative import". So you need to bind the name before you load it. The reason for this is the fundamental invariant of the relative import system: "The invariant holding is that if you have sys.modules['spam'] and sys.modules['spam.foo'] (as you would after the above import), the latter must appear as the foo attribute of the former" as discussed here.

回答5:

It sounds like you don't want to specifically import the configuration file (which has a whole lot of side effects and additional complications involved), you just want to run it, and be able to access the resulting namespace. The standard library provides an API specifically for that in the form of runpy.run_path:

from runpy import run_path
settings = run_path("/path/to/file.py")

That interface is available in Python 2.7 and Python 3.2+

回答6:

You can also do something like this and add the directory that the configuration file is sitting in to the Python load path, and then just do a normal import, assuming you know the name of the file in advance, in this case "config".

Messy, but it works.

configfile = '~/config.py'

import os
import sys

sys.path.append(os.path.dirname(os.path.expanduser(configfile)))

import config

回答7:

You can use the

load_source(module_name, path_to_file) 

method from imp module.

回答8:

I have come up with a slightly modified version of @SebastianRittau's wonderful answer (for Python > 3.4 I think), which will allow you to load a file with any extension as a module using spec_from_loader instead of spec_from_file_location:

from importlib.util import spec_from_loader, module_from_spec
from importlib.machinery import SourceFileLoader 

spec = spec_from_loader("module.name", SourceFileLoader("module.name", "/path/to/file.py"))
mod = module_from_spec(spec)
spec.loader.exec_module(mod)

The advantage of encoding the path in an explicit SourceFileLoader is that the machinery will not try to figure out the type of the file from the extension. This means that you can load something like a .txt file using this method, but you could not do it with spec_from_file_location without specifying the loader because .txt is not in importlib.machinery.SOURCE_SUFFIXES.

回答9:

Here is some code that works in all Python versions, from 2.7-3.5 and probably even others.

config_file = "/tmp/config.py"
with open(config_file) as f:
    code = compile(f.read(), config_file, 'exec')
    exec(code, globals(), locals())

I tested it. It may be ugly but so far is the only one that works in all versions.

回答10:

Do you mean load or import?

You can manipulate the sys.path list specify the path to your module, then import your module. For example, given a module at:

/foo/bar.py

You could do:

import sys
sys.path[0:0] = ['/foo'] # puts the /foo directory at the start of your path
import bar

回答11:

def import_file(full_path_to_module):
    try:
        import os
        module_dir, module_file = os.path.split(full_path_to_module)
        module_name, module_ext = os.path.splitext(module_file)
        save_cwd = os.getcwd()
        os.chdir(module_dir)
        module_obj = __import__(module_name)
        module_obj.__file__ = full_path_to_module
        globals()[module_name] = module_obj
        os.chdir(save_cwd)
    except:
        raise ImportError

import_file('/home/somebody/somemodule.py')

回答12:

I believe you can use imp.find_module() and imp.load_module() to load the specified module. You'll need to split the module name off of the path, i.e. if you wanted to load /home/mypath/mymodule.py you'd need to do:

imp.find_module('mymodule', '/home/mypath/')

...but that should get the job done.

回答13:

You can use the pkgutil module (specifically the walk_packages method) to get a list of the packages in the current directory. From there it's trivial to use the importlib machinery to import the modules you want:

import pkgutil
import importlib

packages = pkgutil.walk_packages(path='.')
for importer, name, is_package in packages:
    mod = importlib.import_module(name)
    # do whatever you want with module now, it's been imported!

回答14:

Create python module test.py

import sys
sys.path.append("<project-path>/lib/")
from tes1 import Client1
from tes2 import Client2
import tes3

Create python module test_check.py

from test import Client1
from test import Client2
from test import test3

We can import the imported module from module.

回答15:

This should work

path = os.path.join('./path/to/folder/with/py/files', '*.py')
for infile in glob.glob(path):
    basename = os.path.basename(infile)
    basename_without_extension = basename[:-3]

    # http://docs.python.org/library/imp.html?highlight=imp#module-imp
    imp.load_source(basename_without_extension, infile)

回答16:

This area of Python 3.4 seems to be extremely tortuous to understand! However with a bit of hacking using the code from Chris Calloway as a start I managed to get something working. Here's the basic function.

def import_module_from_file(full_path_to_module):
    """
    Import a module given the full path/filename of the .py file

    Python 3.4

    """

    module = None

    try:

        # Get module name and path from full path
        module_dir, module_file = os.path.split(full_path_to_module)
        module_name, module_ext = os.path.splitext(module_file)

        # Get module "spec" from filename
        spec = importlib.util.spec_from_file_location(module_name,full_path_to_module)

        module = spec.loader.load_module()

    except Exception as ec:
        # Simple error printing
        # Insert "sophisticated" stuff here
        print(ec)

    finally:
        return module

This appears to use non-deprecated modules from Python 3.4. I don't pretend to understand why, but it seems to work from within a program. I found Chris' solution worked on the command line but not from inside a program.

回答17:

I'm not saying that it is better, but for the sake of completeness, I wanted to suggest the exec function, available in both python 2 and 3. exec allows you to execute arbitrary code in either the global scope, or in an internal scope, provided as a dictionary.

For example, if you have a module stored in "/path/to/module" with the function foo(), you could run it by doing the following:

module = dict()
with open("/path/to/module") as f:
    exec(f.read(), module)
module['foo']()

This makes it a bit more explicit that you're loading code dynamically, and grants you some additional power, such as the ability to provide custom builtins.

And if having access through attributes, instead of keys is important to you, you can design a custom dict class for the globals, that provides such access, e.g.:

class MyModuleClass(dict):
    def __getattr__(self, name):
        return self.__getitem__(name)

回答18:

To import a module from a given filename, you can temporarily extend the path, and restore the system path in the finally block reference:

filename = "directory/module.py"

directory, module_name = os.path.split(filename)
module_name = os.path.splitext(module_name)[0]

path = list(sys.path)
sys.path.insert(0, directory)
try:
    module = __import__(module_name)
finally:
    sys.path[:] = path # restore

回答19:

I made a package that uses imp for you. I call it import_file and this is how it's used:

>>>from import_file import import_file
>>>mylib = import_file('c:\\mylib.py')
>>>another = import_file('relative_subdir/another.py')

You can get it at:

http://pypi.python.org/pypi/import_file

or at

http://code.google.com/p/import-file/

回答20:

Import package modules at runtime (Python recipe)

http://code.activestate.com/recipes/223972/

###################
##                #
## classloader.py #
##                #
###################

import sys, types

def _get_mod(modulePath):
    try:
        aMod = sys.modules[modulePath]
        if not isinstance(aMod, types.ModuleType):
            raise KeyError
    except KeyError:
        # The last [''] is very important!
        aMod = __import__(modulePath, globals(), locals(), [''])
        sys.modules[modulePath] = aMod
    return aMod

def _get_func(fullFuncName):
    """Retrieve a function object from a full dotted-package name."""

    # Parse out the path, module, and function
    lastDot = fullFuncName.rfind(u".")
    funcName = fullFuncName[lastDot + 1:]
    modPath = fullFuncName[:lastDot]

    aMod = _get_mod(modPath)
    aFunc = getattr(aMod, funcName)

    # Assert that the function is a *callable* attribute.
    assert callable(aFunc), u"%s is not callable." % fullFuncName

    # Return a reference to the function itself,
    # not the results of the function.
    return aFunc

def _get_class(fullClassName, parentClass=None):
    """Load a module and retrieve a class (NOT an instance).

    If the parentClass is supplied, className must be of parentClass
    or a subclass of parentClass (or None is returned).
    """
    aClass = _get_func(fullClassName)

    # Assert that the class is a subclass of parentClass.
    if parentClass is not None:
        if not issubclass(aClass, parentClass):
            raise TypeError(u"%s is not a subclass of %s" %
                            (fullClassName, parentClass))

    # Return a reference to the class itself, not an instantiated object.
    return aClass


######################
##       Usage      ##
######################

class StorageManager: pass
class StorageManagerMySQL(StorageManager): pass

def storage_object(aFullClassName, allOptions={}):
    aStoreClass = _get_class(aFullClassName, StorageManager)
    return aStoreClass(allOptions)

回答21:

In Linux, adding a symbolic link in the directory your python script is located works.

ie:

ln -s /absolute/path/to/module/module.py /absolute/path/to/script/module.py

python will create /absolute/path/to/script/module.pyc and will update it if you change the contents of /absolute/path/to/module/module.py

then include the following in mypythonscript.py

from module import *

回答22:

quite simple way: suppose you want import file with relative path ../../MyLibs/pyfunc.py

libPath = '../../MyLibs'
import sys
if not libPath in sys.path: sys.path.append(libPath)
import pyfunc as pf

But if you make it without a guard you can finally get a very long path

回答23:

A simple solution using importlib instead of the imp package (tested for Python 2.7, although it should work for Python 3 too):

import importlib

dirname, basename = os.path.split(pyfilepath) # pyfilepath: '/my/path/mymodule.py'
sys.path.append(dirname) # only directories should be added to PYTHONPATH
module_name = os.path.splitext(basename)[0] # '/my/path/mymodule.py' --> 'mymodule'
module = importlib.import_module(module_name) # name space of defined module (otherwise we would literally look for "module_name")

Now you can directly use the namespace of the imported module, like this:

a = module.myvar
b = module.myfunc(a)

The advantage of this solution is that we don't even need to know the actual name of the module we would like to import, in order to use it in our code. This is useful, e.g. in case the path of the module is a configurable argument.

回答24:

Adding this to the list of answers as I couldn't find anything that worked. This will allow imports of compiled (pyd) python modules in 3.4:

import sys
import importlib.machinery

def load_module(name, filename):
    # If the Loader finds the module name in this list it will use
    # module_name.__file__ instead so we need to delete it here
    if name in sys.modules:
        del sys.modules[name]
    loader = importlib.machinery.ExtensionFileLoader(name, filename)
    module = loader.load_module()
    locals()[name] = module
    globals()[name] = module

load_module('something', r'C:\Path\To\something.pyd')
something.do_something()

回答25:

This answer is a supplement to Sebastian Rittau's answer responding to the comment: "but what if you don't have the module name?" This is a quick and dirty way of getting the likely python module name given a filename -- it just goes up the tree until it finds a directory without an __init__.py file and then turns it back into a filename. For Python 3.4+ (uses pathlib), which makes sense since Py2 people can use "imp" or other ways of doing relative imports:

import pathlib

def likely_python_module(filename):
    '''
    Given a filename or Path, return the "likely" python module name.  That is, iterate
    the parent directories until it doesn't contain an __init__.py file.

    :rtype: str
    '''
    p = pathlib.Path(filename).resolve()
    paths = []
    if p.name != '__init__.py':
        paths.append(p.stem)
    while True:
        p = p.parent
        if not p:
            break
        if not p.is_dir():
            break

        inits = [f for f in p.iterdir() if f.name == '__init__.py']
        if not inits:
            break

        paths.append(p.stem)

    return '.'.join(reversed(paths))

There are certainly possibilities for improvement, and the optional __init__.py files might necessitate other changes, but if you have __init__.py in general, this does the trick.

回答26:

I have wrote my own global and portable import function, based on importlib module, for:

• Be able to import both module as a submodule and to import content of a module to a parent module (or into a globals if has no parent module).
• Be able to import modules with a period characters in a file name.
• Be able to import modules with any extension.
• Be able to use a standalone name for a submodule instead of a file name without extension which is by default.
• Be able to define the import order based on previously imported module instead of dependent on sys.path or on a what ever search path storage.

The examples directory structure:

<root>
 |
 +- test.py
 |
 +- testlib.py
 |
 +- /std1
 |   |
 |   +- testlib.std1.py
 |
 +- /std2
 |   |
 |   +- testlib.std2.py
 |
 +- /std3
     |
     +- testlib.std3.py

Inclusion dependency and order:

test.py
  -> testlib.py
    -> testlib.std1.py
      -> testlib.std2.py
    -> testlib.std3.py 

Implementation:

Latest changes store: https://sourceforge.net/p/tacklelib/tacklelib/HEAD/tree/trunk/python/tacklelib/tacklelib.py

test.py:

import os, sys, inspect, copy

SOURCE_FILE = os.path.abspath(inspect.getsourcefile(lambda:0)).replace('\\','/')
SOURCE_DIR = os.path.dirname(SOURCE_FILE)

print("test::SOURCE_FILE: ", SOURCE_FILE)

# portable import to the global space
sys.path.append(TACKLELIB_ROOT) # TACKLELIB_ROOT - path to the library directory
import tacklelib as tkl

tkl.tkl_init(tkl)

# cleanup
del tkl # must be instead of `tkl = None`, otherwise the variable would be still persist
sys.path.pop()

tkl_import_module(SOURCE_DIR, 'testlib.py')

print(globals().keys())

testlib.base_test()
testlib.testlib_std1.std1_test()
testlib.testlib_std1.testlib_std2.std2_test()
#testlib.testlib.std3.std3_test()                             # does not reachable directly ...
getattr(globals()['testlib'], 'testlib.std3').std3_test()     # ... but reachable through the `globals` + `getattr`

tkl_import_module(SOURCE_DIR, 'testlib.py', '.')

print(globals().keys())

base_test()
testlib_std1.std1_test()
testlib_std1.testlib_std2.std2_test()
#testlib.std3.std3_test()                                     # does not reachable directly ...
globals()['testlib.std3'].std3_test()                         # ... but reachable through the `globals` + `getattr`

testlib.py:

# optional for 3.4.x and higher
#import os, inspect
#
#SOURCE_FILE = os.path.abspath(inspect.getsourcefile(lambda:0)).replace('\\','/')
#SOURCE_DIR = os.path.dirname(SOURCE_FILE)

print("1 testlib::SOURCE_FILE: ", SOURCE_FILE)

tkl_import_module(SOURCE_DIR + '/std1', 'testlib.std1.py', 'testlib_std1')

# SOURCE_DIR is restored here
print("2 testlib::SOURCE_FILE: ", SOURCE_FILE)

tkl_import_module(SOURCE_DIR + '/std3', 'testlib.std3.py')

print("3 testlib::SOURCE_FILE: ", SOURCE_FILE)

def base_test():
  print('base_test')

testlib.std1.py:

# optional for 3.4.x and higher
#import os, inspect
#
#SOURCE_FILE = os.path.abspath(inspect.getsourcefile(lambda:0)).replace('\\','/')
#SOURCE_DIR = os.path.dirname(SOURCE_FILE)

print("testlib.std1::SOURCE_FILE: ", SOURCE_FILE)

tkl_import_module(SOURCE_DIR + '/../std2', 'testlib.std2.py', 'testlib_std2')

def std1_test():
  print('std1_test')

testlib.std2.py:

# optional for 3.4.x and higher
#import os, inspect
#
#SOURCE_FILE = os.path.abspath(inspect.getsourcefile(lambda:0)).replace('\\','/')
#SOURCE_DIR = os.path.dirname(SOURCE_FILE)

print("testlib.std2::SOURCE_FILE: ", SOURCE_FILE)

def std2_test():
  print('std2_test')

testlib.std3.py:

# optional for 3.4.x and higher
#import os, inspect
#
#SOURCE_FILE = os.path.abspath(inspect.getsourcefile(lambda:0)).replace('\\','/')
#SOURCE_DIR = os.path.dirname(SOURCE_FILE)

print("testlib.std3::SOURCE_FILE: ", SOURCE_FILE)

def std3_test():
  print('std3_test')

Output (3.7.4):

test::SOURCE_FILE:  <root>/test01/test.py
import : <root>/test01/testlib.py as testlib -> []
1 testlib::SOURCE_FILE:  <root>/test01/testlib.py
import : <root>/test01/std1/testlib.std1.py as testlib_std1 -> ['testlib']
import : <root>/test01/std1/../std2/testlib.std2.py as testlib_std2 -> ['testlib', 'testlib_std1']
testlib.std2::SOURCE_FILE:  <root>/test01/std1/../std2/testlib.std2.py
2 testlib::SOURCE_FILE:  <root>/test01/testlib.py
import : <root>/test01/std3/testlib.std3.py as testlib.std3 -> ['testlib']
testlib.std3::SOURCE_FILE:  <root>/test01/std3/testlib.std3.py
3 testlib::SOURCE_FILE:  <root>/test01/testlib.py
dict_keys(['__name__', '__doc__', '__package__', '__loader__', '__spec__', '__annotations__', '__builtins__', '__file__', '__cached__', 'os', 'sys', 'inspect', 'copy', 'SOURCE_FILE', 'SOURCE_DIR', 'TackleGlobalImportModuleState', 'tkl_membercopy', 'tkl_merge_module', 'tkl_get_parent_imported_module_state', 'tkl_declare_global', 'tkl_import_module', 'TackleSourceModuleState', 'tkl_source_module', 'TackleLocalImportModuleState', 'testlib'])
base_test
std1_test
std2_test
std3_test
import : <root>/test01/testlib.py as . -> []
1 testlib::SOURCE_FILE:  <root>/test01/testlib.py
import : <root>/test01/std1/testlib.std1.py as testlib_std1 -> ['testlib']
import : <root>/test01/std1/../std2/testlib.std2.py as testlib_std2 -> ['testlib', 'testlib_std1']
testlib.std2::SOURCE_FILE:  <root>/test01/std1/../std2/testlib.std2.py
2 testlib::SOURCE_FILE:  <root>/test01/testlib.py
import : <root>/test01/std3/testlib.std3.py as testlib.std3 -> ['testlib']
testlib.std3::SOURCE_FILE:  <root>/test01/std3/testlib.std3.py
3 testlib::SOURCE_FILE:  <root>/test01/testlib.py
dict_keys(['__name__', '__doc__', '__package__', '__loader__', '__spec__', '__annotations__', '__builtins__', '__file__', '__cached__', 'os', 'sys', 'inspect', 'copy', 'SOURCE_FILE', 'SOURCE_DIR', 'TackleGlobalImportModuleState', 'tkl_membercopy', 'tkl_merge_module', 'tkl_get_parent_imported_module_state', 'tkl_declare_global', 'tkl_import_module', 'TackleSourceModuleState', 'tkl_source_module', 'TackleLocalImportModuleState', 'testlib', 'testlib_std1', 'testlib.std3', 'base_test'])
base_test
std1_test
std2_test
std3_test

Tested in Python 3.7.4, 3.2.5, 2.7.16

Pros:

• Can import both module as a submodule and can import content of a module to a parent module (or into a globals if has no parent module).
• Can import modules with periods in a file name.
• Can import any extension module from any extension module.
• Can use a standalone name for a submodule instead of a file name without extension which is by default (for example, testlib.std.py as testlib, testlib.blabla.py as testlib_blabla and so on).
• Does not depend on a sys.path or on a what ever search path storage.
• Does not require to save/restore global variables like SOURCE_FILE and SOURCE_DIR between calls to tkl_import_module.
• [for 3.4.x and higher] Can mix the module namespaces in nested tkl_import_module calls (ex: named->local->named or local->named->local and so on).
• [for 3.4.x and higher] Can auto export global variables/functions/classes from where being declared to all children modules imported through the tkl_import_module (through the tkl_declare_global function).

Cons:

• [for 3.3.x and lower] Require to declare tkl_import_module in all modules which calls to tkl_import_module (code duplication)

Update 1,2 (for 3.4.x and higher only):

In Python 3.4 and higher you can bypass the requirement to declare tkl_import_module in each module by declare tkl_import_module in a top level module and the function would inject itself to all children modules in a single call (it's a kind of self deploy import).

Update 3:

Added function tkl_source_module as analog to bash source with support execution guard upon import (implemented through the module merge instead of import).

Update 4:

Added function tkl_declare_global to auto export a module global variable to all children modules where a module global variable is not visible because is not a part of a child module.

Update 5:

All functions has moved into the tacklelib library, see the link above.

回答27:

There's a package that's dedicated to this specifically:

from thesmuggler import smuggle

# À la `import weapons`
weapons = smuggle('weapons.py')

# À la `from contraband import drugs, alcohol`
drugs, alcohol = smuggle('drugs', 'alcohol', source='contraband.py')

# À la `from contraband import drugs as dope, alcohol as booze`
dope, booze = smuggle('drugs', 'alcohol', source='contraband.py')

It's tested across Python versions (Jython and PyPy too), but it might be overkill depending on the size of your project.

回答28:

If we have scripts in the same project but in different directory means, we can solve this problem by the following method.

In this situation utils.py is in src/main/util/

import sys
sys.path.append('./')

import src.main.util.utils
#or
from src.main.util.utils import json_converter # json_converter is example method

回答29:

The best way, I think, is from the official documentation (29.1. imp — Access the import internals):

import imp
import sys

def __import__(name, globals=None, locals=None, fromlist=None):
    # Fast path: see if the module has already been imported.
    try:
        return sys.modules[name]
    except KeyError:
        pass

    # If any of the following calls raises an exception,
    # there's a problem we can't handle -- let the caller handle it.

    fp, pathname, description = imp.find_module(name)

    try:
        return imp.load_module(name, fp, pathname, description)
    finally:
        # Since we may exit via an exception, close fp explicitly.
        if fp:
            fp.close()

来源：https://stackoverflow.com/questions/67631/how-to-import-a-module-given-the-full-path