CODEWITHSUNDEEP
pythonpython-2.7module
Raju Ahmed Shetu
Raju Ahmed Shetu

Reputation: 134

Getting Module dynamically

I have some modules like this:

    Drivers/
        a.py
        b.py
        c.py

Now I want to call them on the basis of a variable value. let us consider driver is the variable from where I will get the variable name.

    if driver=='a':
        #then call the driver a and execute.
        a.somefunction()
    if driver=='b':
        #then call the driver b and execute

I know the value we get from the driver in if statement is a string type value and in the if statement we have to call a module. is there any way to convert it.??

Upvotes: 3

Views: 134

Answers (5)

emesday
emesday

Reputation: 6186

If the modules are in the same level(exactly your case), just

module = __import__(driver)
module.somefunction()

driver can be string such as 'a', 'b', or 'c'. If the module does not exist, ImportError is raised.

Upvotes: 2

WKPlus
WKPlus

Reputation: 7255

Or you can use this:

import imp
py_mod = imp.load_module(driver, *imp.find_module(driver, ['Drivers']))

Upvotes: 0

eiPi10
eiPi10

Reputation: 81

You should read here about module search path: https://docs.python.org/2/tutorial/modules.html#the-module-search-path

this discussion shows how to convert string to command: http://www.daniweb.com/software-development/python/threads/198082/converting-string-to-python-code

Basic example for your case would be something like:

assuming a and b are directories in linux in the root

import sys
import os

if driver=='a':
    # add /a to the module search path
    sys.path.append(os.path.join(['/', driver]))

    command_string = 'import ' + driver + '.py'

    # converts a string to python command
    exec(command_string)
    #then call the driver a and execute.
    a.somefunction()
if driver=='b':

    sys.path.append(os.path.join(['/', driver]))

    command_string = 'import ' + driver + '.py'

    # converts a string to python command
    exec(command_string)
    #then call the driver b and execute

Upvotes: 0

Burhan Khalid
Burhan Khalid

Reputation: 174624

Here is another approach:

def default_action():
    print('I will do this by default')
    return 42

the_function = default_action 

if driver == 'a':
    from a import somefunction as the_function
if driver == 'b':
    from b import some_other_function as the_function
if driver == 'c':
    from c import some_other_function as the_function

print('Running the code ... ')
result = the_function()
print('Result is: {}'.format(result))

You'll have to make sure that the full path to Drivers/ is in your PYTHONPATH variable.

Upvotes: 1

Daniel
Daniel

Reputation: 42758

If your "Drivers/" directory in the searchpath of python, simply import the module and call the function:

import importlib
module = importlib.import_module(driver)
module.some_function()

Upvotes: 5

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