Python Runtimeerror: Super() No Arguments
Last Updated : 20 Feb, 2024
Python, a versatile programming language, provides developers with a powerful toolset for creating complex applications. However, like any programming language, it comes with its share of challenges. One such issue that developers might encounter is the "RuntimeError: super(): no arguments." This error can be puzzling for those new to Python 3, but fear not; in this article, we'll explore the nature of this error, understand why it occurs, and delve into different approaches to resolve it.
What is RuntimeError: super(): No Arguments Error?
The "RuntimeError: super(): no arguments" error is a common stumbling block for developers, especially when transitioning from Python 2 to Python 3. This error occurs when using the super() function without providing any arguments, causing confusion and disrupting the inheritance chain. Understanding the reasons behind this error is crucial for finding effective solutions.
Why does RuntimeError: super(): No Arguments occur?
Below are some of the examples by which RuntimeError: super(): No Arguments in Python:
Change in super() Behavior in Python
Python3 introduced a more explicit approach to the super() function, requiring the developer to pass the current class and instance explicitly. Failing to do so results in the RuntimeError.
Python3 class A: @staticmethod def m() -> int: return 1 class B(A): @staticmethod def m() -> int: return super().m() B().m()
Output:
Hangup (SIGHUP)
Traceback (most recent call last):
File "Solution.py", line 11, in <module>
B().m()
File "Solution.py", line 9, in m
return super().m() # passes, but should not
RuntimeError: super(): no arguments
Multiple Inheritance Ambiguity
If your code involves multiple inheritance, not providing arguments to super() can lead to ambiguity in determining the method resolution order (MRO), causing the RuntimeError.
Python3 class Works(type): def __new__(cls, *args, **kwargs): print([cls,args]) # outputs [<class '__main__.Works'>, ()] return super().__new__(cls, args) class DoesNotWork(type): def __new__(*args, **kwargs): print([args[0],args[:0]]) # outputs [<class '__main__.doesNotWork'>, ()] return super().__new__(args[0], args[:0]) DoesNotWork()
Output:
Hangup (SIGHUP)
Traceback (most recent call last):
File "Solution.py", line 11, in <module>
DoesNotWork() # gets "RuntimeError: super(): no arguments"
File "Solution.py", line 9, in __new__
return super().__new__(args[0], args[:0])
RuntimeError: super(): no arguments
Solution for RuntimeError: super(): No Arguments
Below are some of the solutions for RuntimeError: super(): No Arguments error in Python:
Explicitly Pass Class and Instance to super()
To address the change in super() behavior in Python 3, explicitly pass the current class and instance as arguments. For example:
Python3 class ParentClass: def __init__(self): print("ParentClass constructor") class IntermediateClass(ParentClass): def __init__(self): super(IntermediateClass, self).__init__() print("IntermediateClass constructor") class ChildClass(IntermediateClass): def __init__(self): super(ChildClass, self).__init__() print("ChildClass constructor") child_instance = ChildClass() OutputParentClass constructor IntermediateClass constructor ChildClass constructor
Resolve Multiple Inheritance Ambiguity
If your code involves multiple inheritance, carefully review the class hierarchy and ensure that the super() calls are properly aligned with the desired MRO. Adjust the order of the base classes if necessary.
Python3 class ParentA: def show(self): print("Method in ParentA") class ParentB: def show(self): print("Method in ParentB") class Child(ParentA, ParentB): def show(self): super(Child, self).show() print("Method in Child") child_instance = Child() child_instance.show() OutputMethod in ParentA Method in Child
Check and Correct Class Structure
Review your class structure and verify that the super() calls are placed correctly within the methods. Ensure that the inheritance chain is well-defined, and classes are designed according to the intended hierarchy.
Python3 class BaseClass: def __init__(self): print("BaseClass constructor") class IntermediateClass(BaseClass): def __init__(self): super(IntermediateClass, self).__init__() print("IntermediateClass constructor") class ChildClass(IntermediateClass): def __init__(self): super(ChildClass, self).__init__() print("ChildClass constructor") child_instance = ChildClass() OutputBaseClass constructor IntermediateClass constructor ChildClass constructor
Conclusion
The "RuntimeError: super(): no arguments" error in Python 3 can be a stumbling block for developers, but armed with an understanding of its origins and the right solutions, it can be overcome. By embracing the explicit nature of super() in Python 3, resolving multiple inheritance ambiguity, and ensuring a well-structured class hierarchy, developers can navigate through this error and produce robust and efficient Python code.
Similar Reads
Get Current time in Python
In this article, we will know the approaches to get the current time in Python. There are multiple ways to get it. The most preferably date-time module is used in Python to create the object containing date and time. DateTime object in Python is used to manage operations involving time-based data. d
2 min read
How To Create a Countdown Timer Using Python?
In this article, we will see how to create a countdown timer using Python. The code will take input from the user regarding the length of the countdown in seconds. After that, a countdown will begin on the screen of the format 'minutes: seconds'. We will use the time module here. Step-by-Step Approa
2 min read
How to Fix - Timeouterror() from exc TimeoutError in Python
We can prevent our program from getting stalled indefinitely and gracefully handle it by setting timeouts for external operations or long-running computations. Timeouts help in managing the execution of tasks and ensuring that our program remains responsive. In this article, we will see how to catch
3 min read
Create a Countdown Timer for New Year Using Python
Many of us eagerly wait the arrival of the New Year. A countdown timer is a way to keep track of the remaining time until midnight. To achieve this, we'll utilize Python's datetime and time modules. The datetime module allows us to work with dates and times, while the time module helps in creating d
3 min read
Python Super() With __Init__() Method
In object-oriented programming, inheritance plays a crucial role in creating a hierarchy of classes. Python, being an object-oriented language, provides a built-in function called super() that allows a child class to refer to its parent class. When it comes to initializing instances of classes, the
4 min read
Python - Time Strings to Seconds in Tuple List
Given Minutes Strings, convert to total seconds in tuple list. Input : test_list = [("5:12", "9:45"), ("12:34", ), ("10:40", )] Output : [(312, 585), (754, ), (640, )] Explanation : 5 * 60 + 12 = 312 for 5:12. Input : test_list = [("5:12", "9:45")] Output : [(312, 585)] Explanation : 5 * 60 + 12 = 3
7 min read
How to fix "SyntaxError: invalid character" in Python
This error happens when the Python interpreter encounters characters that are not valid in Python syntax. Common examples include: Non-ASCII characters, such as invisible Unicode characters or non-breaking spaces.Special characters like curly quotes (“, â€) or other unexpected symbols.How to Resolve:
2 min read
What Does Super().__Init__(*Args, **Kwargs) Do in Python?
In Python, super().__init__(*args, **kwargs) is like asking the parent class to set itself up before adding specific details in the child class. It ensures that when creating an object of the child class, both the parent and child class attributes are initialized correctly. It's a way of saying, In
4 min read
Python program to print current year, month and day
In this article, the task is to write a Python Program to print the current year, month, and day. Approach: In Python, in order to print the current date consisting of a year, month, and day, it has a module named datetime. From the DateTime module, import date classCreate an object of the date clas
1 min read
Convert string to DateTime and vice-versa in Python
A common necessity in many programming applications is dealing with dates and times. Python has strong tools and packages that simplify handling date and time conversions. This article will examine how to effectively manipulate and format date and time values in Python by converting Strings to Datet
6 min read