Problem Formulation: What does the double colon string[::2] or sequence[3::4] mean in Python? >>> string[::2] You can observe a similar double colon :: for sequences: >>> lst = [1, 2, 3, 4, 5, 6, 7, 8, 9] >>> lst[::2] Answer: The double colon is a special case in Python’s extended slicing feature. The extended slicing … Read more
Problem Formulation: Compare RPM Versions in Python Given two lists of strings that are the RPM versions currently installed on your computer and the versions in a repository or another environment. How to compare those lists to find the RPMs that are out of date? Example: Our goal is to determine a list of packages … Read more
In this tutorial you will learn about doubly linked list. You will learn how to implement a doubly linked list in Python. A doubly linked list, unlike a singly linked lists consists of a data value along with a next and previous pointer. Let us see a simple example of a doubly linked list. In … Read more
Python’s built-in reversed(sequence) function returns a reverse iterator over the values of the given sequence such as a list, a tuple, or a string. Usage Learn by example! Here are some examples of how to use the reversed() built-in function. The most basic use is on a Python list: You can see that the return … Read more
Problem Formulation: Given a Python object. How to check if the given Python object is of type list? Example: Given a dictionary for which you don’t know the values associated to the keys. For example, suppose you have entry dict[key] for which you don’t know the type. How to check if it’s a list? Given: … Read more
Python’s built-in set() function creates and returns a new set object. A set is an unordered collection of unique elements. Without an argument, set() returns an empty set. With the optional argument, set(iter) initializes the new set with the elements in the iterable. Read more about sets in our full tutorial about Python Sets. Usage … Read more
In this blog post you will learn how to implement a linked list in Python from scratch. We will understand the internals of linked lists, the computational complexity of using a linked list and some advantages and disadvantages of using a linked list over an array. Introduction Linked list is one of the most fundamental … Read more
Hey Finxters! It is time for another Python subject that will come up for sure within your Python developer career. Problem Formulation: How to iterate over a generator twice? Then we will look at three solutions on how we can iterate twice, or even multiple times, over a generator or iterator. First, we must understand … Read more
Python’s built-in filter() function is used to filter out elements that pass a filtering condition. It takes two arguments: function and iterable. The function assigns a Boolean value to each element in the iterable to check whether the element will pass the filter or not. It returns an iterator with the elements that pass the … Read more
Summary: To iterate over the dictionary items in random order get the list of items in a tuple with .items() or get the list of keys with .keys() or extract the values in a list using .values() , then shuffle and iterate through this list using the shuffle() method of the random module. Problem: Given a … Read more
Python’s built-in function len() returns the length of the given string, array, list, tuple, dictionary, or any other iterable. The type of the return value is an integer that represents the number of elements in this iterable. Usage Learn by example! Here are some examples on how to use the len() built-in function. The examples … Read more
Summing up numbers is one of those repetitive tasks you need to do over and over again in your practical code projects. To help you accomplish this task in a concise, readable, and efficient way, Python’s creators have added the built-in sum() function. It sums over all elements in a Python list—or any other iterable … Read more