Dictionary values to call methods of classes

Question

I have a dictionary that has function names, i. e.

dict = {
    'family1' :
        ['classA(param1=555','classB(param1=777)'] }

Now I would like to call the methods of the classes like so:

myclass = dict['family1'][0]
myclass.method()

However, I'm getting str object does not have the method() (but it definitely has it, however I seems the myclass is not recognized and stays a string.

BEST ANSWER: Remove '' from ['functioname'] so that the dictionary does not have strings but actual function references in it. Then calls will not reference a string but a function reference.

Possible duplicate of [Calling a function of a module by using its name (a string)](https://stackoverflow.com/questions/3061/calling-a-function-of-a-module-by-using-its-name-a-string) — Jeppe, Jun 09 '19 at 19:32
you should check lambda or functools.partial. How many parameters your functions have? — Jean-François Fabre, Jun 09 '19 at 19:32
If `functionname` is an actual function in the scope, what about a lambda? `lambda *args: functionname(*args, param1=6398)` — N Chauhan, Jun 09 '19 at 19:33
@Jean-FrançoisFabre: Not more than 5 for any of the functions that I use. — , Jun 09 '19 at 19:35
Could you be looking for `eval`? https://docs.python.org/3/library/functions.html#eval — Baleato, Jun 09 '19 at 19:35
please provide more real functions. You want to bind a parameter to a function and leave the others settable? use `lambda` or `functools.partial` and don't use strings. — Jean-François Fabre, Jun 09 '19 at 19:36
@Jean-FrançoisFabre: Parameters could be left out, if need be, however I'd like to iterate through a dictionary of classes names and call methods on them one by one depending on which class is selected. Within those calls I need to call methods. — , Jun 09 '19 at 19:44

score 1 · Answer 1 · answered Jun 09 '19 at 19:45

You should place actual functions in your dictionary. Functions and lambdas in Python are first class types so you can use them in data.

functions = {
    'family1' :
        [lambda:classB(param1=555), lambda:classB(param1=777)],
    'family2' :
        [lambda:functionname(param1=6981),lambda:functionname(param1=9333)] }

def functionname(param1): print(param1)

functions['family2'][0]() # prints 6981

functions['family1'][0]() # returns classB(param1=555)

score 1 · Answer 2 · answered Jun 09 '19 at 20:09

dict = {
    'family1' :
        ['classA(param1=555)','classB(param1=777)'] }

class classA():

    def __init__(self,param1):
        self.param=param1
    def method(self):
        print("A",self.param)

class classB():

    def __init__(self, param1):
        self.param = param1
    def method(self):
        print("B",self.param)

myclass = dict['family1'][0]
eval(myclass).method()
myclass = dict['family1'][1]
eval(myclass).method()

Dictionary values to call methods of classes

2 Answers2