In Python, “dunder” methods, short for “double underscore” methods, are special methods that allow developers to define the behavior of built-in operations for custom objects. For instance, when you use the + operator to add two objects, Python internally calls the __add__ method. Similarly, other operators have their corresponding dunder methods. However, the term “not … Read more
Do you encounter the following error message? TypeError: ‘dict_values’ object is not subscriptable You’re not alone! This short tutorial will show you why this error occurs, how to fix it, and how to never make the same mistake again. So, let’s get started! Solution Python raises the “TypeError: ‘dict_values’ object is not subscriptable” if you … Read more
Do you encounter the following error message? TypeError: ‘dict_keys’ object is not subscriptable You’re not alone! This short tutorial will show you why this error occurs, how to fix it, and how to never make the same mistake again. So, let’s get started! Solution Python raises the “TypeError: ‘dict_keys’ object is not subscriptable” if you … Read more
The “TypeError: ‘method’ object is not subscriptable” occurs when you call a method using square brackets, e.g., object.method[3]. To fix it, call the non-subscriptable method only with parentheses like so: object.method(3). How Does the Error Occur (Example) In the following minimal example, you attempt to define a custom “list” class and you try to access … Read more
Problem Formulation Consider the following minimal example where a TypeError: ‘bool’ object is not subscriptable occurs: This yields the following output: Solution Overview Python raises the TypeError: ‘bool’ object is not subscriptable if you use indexing or slicing with the square bracket notation on a Boolean variable. However, the Boolean type is not indexable and … Read more
Problem Formulation Consider the following minimal example where a TypeError: ‘float’ object is not subscriptable occurs: This yields the following output: Solution Overview Python raises the TypeError: ‘float’ object is not subscriptable if you use indexing or slicing with the square bracket notation on a float variable that is not indexable. However, the float class … Read more
Do you encounter the following error message? TypeError: NoneType is not subscriptable You’re not alone! This short tutorial will show you why this error occurs, how to fix it, and how to never make the same mistake again. So, let’s get started! Summary Python raises the TypeError: NoneType is not subscriptable if you try to … Read more
Python __version__ Attribute Python contains many “Magic Methods/Attributes”. One of these is __version__ commonly called “Dunder version” because of the double underscore before and after version. In this article, I will briefly look at what a Dunder Method/Attribute is and talk about __version__. What Does a Dunder Method/Attribute Do? Dunder Methods/Attributes, also called “Magic Methods” … Read more
The TypeError: unhashable type: ‘list’ usually occurs when you try to use a list object as a set element or dictionary key and Python internally passes the unhashable list into the hash() function. But as lists are mutable objects, they do not have a fixed hash value. The easiest way to fix this error is … Read more
object.__aiter__(self) object.__anext__(self) 💡 Summary: Python’s __aiter__() and __anext__() methods are used to implement an asynchronous for loop (keywords: async for). In contrast to a normal (synchronous) for loop, an asynchronous for loop iterates over an asynchronous source. __aiter__() returns an asynchronous iterator object (in many cases it’s simply a reference to itself: return self) __anext__() … Read more
object.__aexit__(self, exc_type, exc_val, exc_tb) 💡 Summary: Python’s __aexit__() magic method is semantically similar to __exit__() but is used for asynchronous and parallel programming. Python calls the __aexit__() magic method when leaving an async with block whereas the __aenter__() method is called when entering it. An object that implements both __aenter__() and __aexit__() methods is called … Read more
object.__aenter__(self) 💡 Summary: Python’s __aenter__() magic method is semantically identical to __enter__() but is used for asynchronous and parallel programming. Python calls the __aenter__() magic method when starting an async with block whereas the __aexit__() method is called when leaving it. An object that implements both __aenter__() and __aexit__() methods is called an asynchronous context … Read more