How to Call Python Functions Dynamically

How to call Python functions dynamically

If don't want to use globals, vars and don't want make a separate module and/or class to encapsulate functions you want to call dynamically, you can call them as the attributes of the current module:

import sys
...
getattr(sys.modules[__name__], "clean_%s" % fieldname)()

What's the way to call a function dynamically in Python?

Functions are first class objects. So like this:

def do_this():
    print "In do_this"

def do_that():
    print "In do_that"

dct = [do_this, do_that]
dct[0]()

If you really want to call them from a string list you can use globals():

dct = ['do_this', 'do_that']
globals()[dct[0]]()

But I would suggest that using globals() (or locals()) probably isn't the right way to solve your problem. Grok the python way: >>> import this

How to generate dynamic function name and call it using user input in Python

if the mapping is static, either make a mapping of function name to function object

mapping = {
  "pattern_1": pattern_1,
  "pattern_2": pattern_2
}

#do not use `eval` on user input!
pattern_no = input('Enter pattern num [1-10]: ')

cust_fun_name = 'pattern_' + str(pattern_no)
cust_func = mapping[cust_fun_name]
# call the function
cust_func()

or get the function object directly from the local namespace

cust_func = locals()['pattern_' + str(pattern_no)]
cust_func()

Dynamic Function Calling From a Different File - Python

In file1.py, add a function dictionary like this:

function_dict = {'one':one, 'two':two, 'three':three}

Then in file2.py, replace file1.function_id() with this:

file1.function_dict[function_id]()

How to dynamically create functions in python

Just found out the answer. The best way to dynamically create the function is to not create it at all. It kind of conflicts with my question but still solves the problem. The idea is to put a structure of a function as key in a dictionary and a line of the beginning of the function as a value. So now it is possible by structure of the function find it, execute and then return to normal execution by saving the last line of Main in advance.

Calling a function of a module by using its name (a string)

Given a module foo with method bar:

import foo
bar = getattr(foo, 'bar')
result = bar()

getattr can similarly be used on class instance bound methods, module-level methods, class methods... the list goes on.

How to dynamically call different functions based on user input

Since functions are objects in Python, it's easy to make a dictionary pairing keywords with functions.

action_dict = {'add': add,
               'sub': sub,
               # ...
              }

if operation in action_dict:
    action_dict[operation](num1, num2)

How to call Python function by name dynamically using a string?

You can use the getattr function:

import torchvision

model_name = 'resnet18'
model = getattr(torchvision.models, model_name)(pretrained=configs.use_trained_models)

This essentially is along the lines the same as the dot notation just in function form accepting a string to retrieve the attribute/method.

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