CODEWITHSUNDEEP
pythonpython-3.xoop
psychedelic-snail
psychedelic-snail

Reputation: 363

TypeError: missing 1 required position argument in Python 3 during object call

I am writing a program in Python 3 that creates objects from a class, and from these objects I can run some calculations. However, when I instantiate my object and try to run it's methods, I get the following error: TypeError: method1() missing 1 required positional argument: 'index'. Here is an example of the code:

class Foo:
       def __init__(self, var1, var2, var3):
           """var1 and var2 are lists"""
           self.var1 = var1 
           self.var2 = var2
           self.var3 = var3

       def method1(self, index):
           return self.var3 * (self.var1[index] + self.var2[index])

       def run_calculation(self):
           for i in range(1,10):
               self.var1.append(Foo.method1(i))
               self.var2.append(Foo.method1(i))

When I try to run this code like so:

a = Foo([1],[2],3)
a.run_calculation()

I get the error described above. method1 always gets passed the argument necessary when it is called during run_calculation, so I don't see the problem. Thank you in advance!

Upvotes: 0

Views: 422

Answers (2)

Sazzad
Sazzad

Reputation: 853

you are calling it like class method. here is the correct version.

class Foo:
def __init__(self, var1, var2, var3):
    """var1 and var2 are lists"""
    self.var1 = var1
    self.var2 = var2
    self.var3 = var3

def method1(self, index):
    return self.var3 * (self.var1[index] + self.var2[index])

def run_calculation(self):
    for i in range(1, 10):
        self.var1.append(self.method1(i))
        self.var2.append(self.method1(i))

    print(self.var1, self.var2)

a = Foo([1,2], [3,4], 5)
a.run_calculation()

Upvotes: 0

RomainL.
RomainL.

Reputation: 1014

The problem here is that you call that method as a static one. you need to use self instead of Foo. in run_calculation()

class Foo:
       def __init__(self, var1, var2, var3):
           """var1 and var2 are lists"""
           self.var1 = var1 
           self.var2 = var2
           self.var3 = var3

       def method1(self, index):
           return self.var3 * (self.var1[index] + self.var2[index])

       def run_calculation(self):
           for i in range(1,10):
               self.var1.append(self.method1(i))   # notice the self here
               self.var2.append(self.method1(i))  # notice the self here

Upvotes: 1

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