Python List

How To Eliminate All The Whitespace From A String?

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 …

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Slice Notation – A Simple Illustrated Guide

Summary: Slicing is a Python concept to extract a subsequence from a string or list—that lies within a start and stop index range. There are two syntactical ways to define a slice. (1) The extended slice notation makes use of a colon : in string_name[start:stop:step]. (2) The slice() constructor defines the index range in string_name[slice(start:stop:step)]. …

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How To Pass a Variable By Reference In Python?

Summary: Variables are passed by object reference in Python. Therefore, mutable objects are passed by reference while immutable objects are passed by value in Python. To pass immutable objects by reference you can return and reassign the value to the variable, or pass it inside a dictionary/list, or create a class and use the self …

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Python Reverse List with Slicing — An Illustrated Guide

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 …

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How to Remove Duplicates From a Python List While Preserving Order?

To remove duplicates from a Python list while preserving the order of the elements, use the code list(dict.fromkeys(list)) that goes through two phases: (1) Convert the list to a dict using the dict.fromkeys() function with the list elements as keys and None as dict values. (2) Convert the dictionary back to a list using the …

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How to Get the Last Element of a Python List?

Problem: Given a list. How to access the last element of this list? Example: You have the list [‘Alice’, ‘Bob’, ‘Liz’] and you want to get the last element ‘Liz’. Quick solution: Use negative indexing -1. To access the last element of a Python list, use the indexing notation list[-1] with negative index -1 which …

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List Changes After Assignment — How to Clone or Copy It?

Problem: If you assign a list object to a new variable using new_list = old_list, any modification to new_list changes old_list. What’s the reason for this and how can you clone or copy the list to prevent this problem? Example: Let’s consider the following example. Appending an element to the new_list also modifies the original …

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56 Python One-Liners to Impress Your Friends

This is a running document in which I’ll answer all questions regarding the single line of Python code. It’s based on my interactive collection here but without the slow videos and embedded code shells. Let’s get started! Python One Line If Else You can use a simple if statement in a single line of code. …

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