Q: What’s the object-oriented way to become wealthy? A: Inheritance. ? Your vocabulary determines the reality of your life. In this tutorial, I have compiled the most essential terms and concepts of object-oriented programming in Python. My goal was to create the best Python OOP cheat sheet that shows them in one place. Well — … Read more
To join specific list elements (e.g., with indices 0, 2, and 4) and return the joined string that’s the concatenation of all those, use the expression ”.join([lst[i] for i in [0, 2, 4]]). The list comprehension statement creates a list consisting of elements lst[0], lst[2], and lst[4]. The ”.join() method concatenates those elements using the … Read more
Slicing is a concept to carve out a substring from a given string. Use slicing notation s[start:stop:step] to access every step-th element starting from index start (included) and ending in index stop (excluded). All three arguments are optional, so you can skip them to use the default values (start=0, stop=len(lst), step=1). For example, the expression … Read more
To join and replace all strings in a list lst between start index 1 and end index 5, use the one-liner lst[1:5] = [”.join(lst[1:5])]. This solution is based on slice assignment that selects the slice you want to replace on the left and the values to replace it on the right side of the assignment. … Read more
Do you want to join a list of strings to a path in your specific operating system? Remembering the correct path separator can be a real pain. Fortunately, the os.path.join() method comes to the rescue! The os.path.join() method takes one or more path arguments and returns a concatenation of the path arguments with the correct … Read more
Given a list of strings. Join the first with the second string, the second with the third, and so on. The one-liner [lst[i] + lst[i+1] for i in range(0, len(lst), 2)] solves the problem by using the range function to iterate over every other index i=0, 2, 4, 5, … to concatenate the i-th and … Read more
🛑 Note: Python has zero-based indexing, i.e., the index of the first element is 0, and the index of the i-th element is (i-1). Not considering zero-based indexing but assuming the i-th element has index i is a common source of bugs! Here’s an example that demonstrates how list indexing works in Python: 🏃 Training … Read more
To join a list of Unicode strings in Python, use the string.join(list) method on the delimiter string. For example, you can call ‘?’.join([‘⭐’, ‘?’, ‘?’]) to obtain the string ‘⭐????’. Note that per default, all strings are UTF-8 in Python which means they already are Unicode encoded. This morning—when reading a WhatsApp message during my … Read more
The most Pythonic way to merge multiple lists l0, l1, …, ln into a list of tuples (grouping together the i-th elements) is to use the zip() function zip(l0, l1, …, ln). If you store your lists in a list of lists lst, write zip(*lst) to unpack all inner lists into the zip function. The … Read more
If the search phrase “Python Join List Range” brought you here, you’re having most likely one of the following problems: You don’t know how to concatenate two range() iterables, or You want to use .join() to create a string from a range() iterable—but it doesn’t work. In any case, by reading this article, I hope … Read more
The most efficient method to join a list of Python strings in reverse order is to use the Python code ”.join(l[::-1]). First, reverse the list l using slicing with a negative step size l[::-1]. Second, glue together the strings in the list using the join(…) method on the empty string ”. Problem: Given a list … Read more
Little time to learn NumPy? This article shows you the ten most amazing NumPy cheat sheets. Download them, print them, and pin them to your wall — and watch your data science skills grow! ?? All NumPy cheat sheets in this article are 100% free. All links open in a new tab (so feel free … Read more