Python’s built-in iter() function returns an iterator for the given object. For example, iter([1, 2, 3]) creates an iterator for the list [1, 2, 3]. You can then iterate over all elements in the iterator, one element at a time, in a for or while loop such as: for x in iter([1, 2, 3]). Basic … Read more
Python’s built-in slice() function returns a new slice object you can use to slice over sequences such as lists, strings, or tuples. Read more about lists in our full tutorial about Python Slicing. Example 1: Slice with Stop Argument One of the best way to learn is by example! Here are some examples of how … Read more
Python’s built-in open() function opens a file and returns a file object. The only non-optional argument is a filename as a string of the file to be opened. You can use the file object to access the file content. For example, file_obj.readlines() reads all lines of such a file object. Here’s a minimal example of … Read more
Python’s built-in super() method returns a temporary object of the superclass to help you access its methods. Its purpose is to avoid using the base class name explicitly. It also enables your class to inherit from multiple base classes. Visual Idea super() The idea is simple: use super() to call the methods defined in the … Read more
Python’s built-in input() function reads a string from the standard input. The function blocks until such input becomes available and the user hits ENTER. You can add an optional prompt string as an argument to print a custom string to the standard output without a trailing newline character to tell the user that your program … Read more
The Python memoryview(arg) function returns a memoryview object of the given bytes or bytearray argument. This exposes the argument’s internal data (buffers) to help you access the data without intermediate copying. Syntax: memoryview(object) Arguments object Bytes or Bytearray object for which the memoryview should be returned Return Value memoryview Returns memoryview of the object. Python … Read more
Python’s built-in hash(object) function takes one object as an argument and returns its hash value. As the hash value is calculated based on the object’s data, two different but equal objects must have the same hash value. It doesn’t follow, though, that two objects with the same hash value are equal—they can have the same … Read more
Python’s built-in hex(integer) function takes one integer argument and returns a hexadecimal string with prefix “0x”. If you call hex(x) on a non-integer x, it must define the __index__() method that returns an integer associated to x. Otherwise, it’ll throw a TypeError: object cannot be interpreted as an integer. Argument integer An integer value or … Read more
Python’s built-in oct(integer) function takes one integer argument and returns an octal string with prefix “0o”. If you call oct(x) on a non-integer x, it must define the __index__() method that returns an integer associated to x. Otherwise, it’ll throw a TypeError: object cannot be interpreted as an integer. Argument integer An integer value or … Read more
Object-orientation is great way to encapsulate data in your application. This minimizes complexity and adheres to good software engineering principles. However, attributes in Python can be easily accessed from the outside—they’re not really encapsulated. That’s one of the reason the property() built-in function exists: it allows you to truly encapsulate data with the means of … Read more
Python’s built-in id(object) function takes a Python object as an input and returns the identity of an object that is a static, unique integer. The identity is static, it never changes throughout the program’s execution, and unique, no other object has the same identity. It is implemented in cPython by returning the address of the … Read more
Python’s built-in vars() function returns the __dict__ attribute of an object—a dictionary containing the object’s changeable attributes. Without argument, it returns the local symbol table similar to locals(). Python’s built-in vars() function returns a dictionary of name: value mappings of all the names defined in the local scope or the scope of the optional object … Read more