5 Best Ways to Use Python Regex to Find Sequences of One Upper Case Letter Followed by Lower Case Letters

πŸ’‘ Problem Formulation: The task is to employ Python’s regex (regular expressions) capabilities to identify sequences where an uppercase letter is immediately followed by lowercase letters. For example, given the input string “Hello World”, the desired output would be [“Hello”]. Method 1: Using the re.findall() Function Python’s re.findall() function is ideal for scanning a string … Read more

5 Best Ways to Create MultiIndex from Arrays in Python Pandas

πŸ’‘ Problem Formulation: When working with complex data in Python’s Pandas library, you might need to group by multiple levels of indexing (hierarchical indexing) for advanced data analysis. Creating a MultiIndex from arrays is essential for such tasks. For example, you might have two arrays [‘a’, ‘a’, ‘b’, ‘b’] and [1, 2, 1, 2] which … Read more

5 Best Ways to Remove All Characters Except Letters and Numbers in Python

πŸ’‘ Problem Formulation: When working with strings in Python, you might encounter situations where you need to retain only alphanumeric characters (letters and numbers) and discard all other characters such as punctuation, whitespace, or special symbols. For instance, given an input string ‘Hello, World! 123.’, you aim to output ‘HelloWorld123’. Method 1: Using Regular Expressions … Read more

5 Best Ways to Filter a Pandas DataFrame by Time

πŸ’‘ Problem Formulation: When working with dataset containing time series data, a common task is to filter records based on time criteria. For example, you may have a DataFrame of stock prices and you wish to filter out entries that fall outside of regular trading hours or beyond a certain date range. The desired output … Read more

5 Best Ways to Remove Palindromic Elements from a Python List

πŸ’‘ Problem Formulation: This article guides Python developers on different methodologies to filter out palindromic elements from a list. Palindromes are words or phrases that read the same backward as forward, like “radar” or “level”. Given a list such as [‘python’, ‘refer’, ‘did’, ‘hello’, ‘noon’], the expected output after removing palindromic elements would be [‘python’, … Read more