The Fibonacci series was discovered by the Italian mathematician Leonardo Fibonacci in 1202 and even earlier by Indian mathematicians. The series appears in unexpected areas such as economics, mathematics, art, and nature. Algorithm Sketch In the following, we give a simple algorithm to calculate the Fibonacci numbers. The series starts with the Fibonacci numbers zero …
Python’s exec() function executes the Python code you pass as a string or executable object argument. This is called dynamic execution because, in contrast to normal static Python code, you can generate code and execute it at runtime. This way, you can run programmatically-created Python code. Have you ever wondered about the limits of a …
Python exec() — A Hacker’s Guide to A Dangerous Function Read More »
The most pythonic way to convert a list of integers fs to a list of floats is to use the one-line fs = [float(x) for x in fs]. It iterates over all the elements in the list fs using list comprehension and converts each element of the list x to an integer value using the …
How to Convert an Integer List to a Float List in Python Read More »
Python slicing means to access a subsequence of a sequence type using the notation [start:end]. A little-known feature of slicing is that it has robust end indices. Slicing is robust even if the end index is greater than the maximal sequence index. The slice just takes all elements up to the maximal element. If the …
Why Slicing With Index Out Of Range Works In Python? Read More »
When I first saw this, I was sure it’s a bug. Well—it’s a feature! In today’s short article, you’ll learn about a small Python trick that I call “string concatenation without +”. Let’s start with some code! Plus vs. Adjacent String Literal Concatenation There are two ways to concatenate string literals in Python: Using the …
If you work in a data driven career, odds are you will at some point have to perform sorting on your data. Rather than writing your own sorting algorithm (which will most likely be far less efficient), Python provides a built-in function called sorted(). This function allows you to do basic sorting, such as arranging …
To convert an integer i to a string with leading zeros so that it consists of 5 characters, use the format string f'{i:05d}’. The d flag in this expression defines that the result is a decimal value. The str(i).zfill(5) accomplishes the same string conversion of an integer with leading zeros. Challenge: Given an integer number. …
Have you ever had a string and wanted to make it a certain length by adding zeros to it? You could type it out. But we’re programmers, we hate typing! Surely there must be a way to code this? To pad zeros to a string, use the str.zfill() method. It takes one argument: the final …
Question: Is it possible to call a function inside a list comprehension statement? Background: List comprehension is a compact way of creating lists. The simple formula is [expression + context]. Expression: What to do with each list element? Context: What elements to select? The context consists of an arbitrary number of for and if statements. …
The most Pythonic way to convert a list of floats fs to a list of integers is to use the one-liner fs = [int(x) for x in fs]. It iterates over all elements in the list fs using list comprehension and converts each list element x to an integer value using the int(x) constructor. This …
How to Convert a Float List to an Integer List in Python Read More »
In this article, you’ll learn the ultimate answer to the following question: How To Eliminate All The Whitespace From A String—on Both Ends, and In-Between Words? Summary: Use the string methods join(), split(), strip(), rstrip(), lstrip() and or replace()—in specific combinations—to remove any whitespace in a given string. The simplest way to remove all whitespaces …
How To Eliminate All The Whitespace From A String? Read More »
Summary: The slice notation list[::-1] with default start and stop indices and negative step size -1 reverses a given list. Problem: Given a list of elements. How to reverse the order of the elements in the list. Example: Say, you’ve got the following list: Your goal is to reverse the elements to obtain the following …
Python Reverse List with Slicing — An Illustrated Guide Read More »
