Question

I need to define a class that will take multiple keyword parameters.

My code looks like this:

class test1:
    def __init__(self,parm1=val1, parm2=val2):
        self.x = parm1
        self.y = parm2
        print('parm1',self.x)


def main():
    x = test1(1,2)

but I get an error that val1 is not defined. What would be the proper way ?

Answer 1

You need to define val1 and val2 before you define your class test:

val1 = 1
val2 = 3.141592653

class test(object):
    def __init__(self, param1=val1, param2=val2):
        self.x = param1
        self.y = param2

This approach can have its advantages (say, if val1 and val2 should be some generic default values read from the environment…), but is not really readable. It’d be best to use something like:

class test(object):
    def __init__(self, param1=None, param2=None):
        if param1 is None:
            self.x = val1
        else: 
            self.x = val2

where once again, val1 and val2 are defined before the definition of test…