The ‘_’.join(list) method on the underscore string ‘_’ glues together all strings in the list using the underscore string as a delimiter—and returns a new string. For example, the expression ‘_’.join([‘a’, ‘b’, ‘c’]) returns the new string ‘a_b_c’. Definition and Usage The string.join(iterable) method joins the string elements in the iterable to a new string …
Python Join List with Underscore [The Most Pythonic Way] Read More »
Short answer: To flatten your list of list lst, use the nested list comprehension [x for l in lst for x in l] to iterate over all nested lists (for l in lst) and over all their elements (for x in l). Each element x, you just place in the outer list, unchanged. When browsing …
How to Join a List of Lists? You Don’t. You Flatten It! Read More »
In Python, there are always multiple ways to accomplish the same thing—but with subtle differences in the side effects. A great coder will always choose the most effective way for the problem at hand. This tutorial shows you six different ways to add elements to a list in Python. In a nutshell, the different ways …
The Python built-in list data type is powerful. However, the NumPy array has many advantages over Python lists. What are they? Advantages NumPy Advantages Python Lists Multi-dimensional Slicing Library-Independent Broadcasting Functionality Intuitive Processing Speed Less Complicated Memory Footprint Heterogeneous List Data Allowed Many Convenience Methods Arbitrary Data Shape (Non-Square Matrix) Let’s dive into the most …
[NumPy vs Python] What are Advantages of NumPy Arrays over Regular Python Lists? Read More »
Do you want to convert a Python set to a list? Use the list(…) constructor and pass the set object as an argument. For example, to convert a set of strings friends into a list, use the code expression list(friends). Here’s an example code snippet that converts the set to a list using the list(…) …
Do you have a list but you want to convert it to a Python set? No problem! Use the set(…) constructor and pass the list object as an argument. For example, if you have a list of strings friends, you can convert it to a set using the call set(friends). Here’s an example code snippet: …
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Problem: Given a dictionary and a filter condition. How to filter a dictionary by … … key so that only those (key, value) pairs in the dictionary remain where the key satisfies the condition? … value so that only those (key, value) pairs remain where the value satisfies the condition? In this tutorial, you’ll learn …
How to Filter a Dictionary in Python? (… The Most Pythonic Way) Read More »
In this tutorial, you’ll learn the runtime complexity of different Python operations. Then, you’ll learn how to calculate the complexity of your own function by combining the complexity classes of its constituents. This is called “static analysis” The tutorial is loosely based on (source) but it extends it significantly with more practical examples, interactive snippets, …
What is the Tilde ~ in Python? Python’s Tilde ~n operator is the bitwise negation operator: it takes the number n as binary number and “flips” all bits 0 to 1 and 1 to 0 to obtain the complement binary number. For example, the tilde operation ~1 becomes 0 and ~0 becomes 1 and ~101 …
To add an element to a given Python list, you can use either of the three following methods: Use the list insert method list.insert(index, element). Use slice assignment lst[index:index] = [element] to overwrite the empty slice with a list of one element. Use list concatenation with slicing lst[:2] + [‘Alice’] + lst[2:] to create a …
How to Add an Element to a Python List at an Index? Read More »
Short answer: To find the minimal list in a list of lists, you need to make two lists comparable. How? With the key argument of the min() function. The key argument is a function that takes one input (a list) and returns one output (a numerical value). The list with the smallest numerical value is …
How to Find the Minimum of a List of Lists in Python? Read More »
Short answer: To find the maximal list in a list of lists, you need to make two lists comparable. How? With the key argument of the max() function. The key argument is a function that takes one input (a list) and returns one output (a numerical value). The list with the largest numerical value is …
How to Find the Max of a List of Lists in Python? Read More »