Define a class with optional argument in Python

Question

class class1():
    def setdata(self,value1, value2):
    self.data = value1+value2
def display(self):
    print(self.data)

For the above code, when I use it. It will require exactly two arguments.

>>>a = class1()
>>>a.setdata('123','456')

But what if I want to set a default value for value2, for exmaple, its(value2) default value is '000'.

Next time when I use the class, I can either type

>>>a = class1()
>>>a.setdata('123')

a.data will be '123000'

Or I can type

>>>a = class1()
>>>a.setdata('123','654')

a.data will be '123654'

How to achieve this? Thanks very much!

Solution 1

Try this please:

def setdata(self, value1, value2 = '000'):
   Your code here

Solution 2

Try defining a default argument, like so.

class class1():
    def setdata(self,value1, value2='000'):
        ...

Solution 3

class class1:    
    def setdata(self,value1, value2=456):
        self.data = value1+value2
    def display(self):
        print(self.data)

may be this solves your problem

Comments

[Li-aung Yip]

You should try to link to a newer version of the Python documentation. Python 1.x is a historical fossil these days.

[XORcist]

For an explanation including the point where most people trip over: network-theory.co.uk/docs/pytut/DefaultArgumentValues.html

[cheeken]

@Li-aungYip Excellent point, I will update the link. I was posting from my phone, so my requirements may have been lax. :)

[Mausy5043]

pep8 recommends no spaces around equalsign.