Summary The issue occurs because inserting rows shifts existing row indices downward, but the code continues to write to the original, calculated indices. In openpyxl, inserting rows at a specific point physically moves existing rows down to make space. Data written to the original row numbers after insertion overwrites what used to be there or … Read more
Summary A developer asked for a “simple” Python solution to find strings in a list that share the longest common prefix with a given input string. While simple one-liners exist, they hide catastrophic performance pitfalls and memory exhaustion risks in production environments. The core task requires comparing an input string against a list of candidates … Read more
Summary A candidate submitted a Python script intended to identify all strings from an input file that appear as a substring of at least one other distinct string in the list. The script uses nested loops and the in operator to perform this check. While the code syntactically functions, the underlying algorithmic approach and file … Read more
Summary This postmortem addresses a common architectural misunderstanding when migrating from legacy WebClient/WebRequest APIs to HttpClient in .NET 9. The developer encountered 404 (Not Found) and 405 (Method Not Allowed) errors while attempting to perform file operations (Upload, Rename, Delete) on an IIS 10 web server. The core issue is not a code syntax error, … Read more
Summary The user is experiencing a race condition between the React Router navigate function and the Redux state update triggered by dispatch(logout()). The attempt to navigate to the homepage (/) in Header.jsx is being immediately overridden by the ProtectedRoute component. When the user clicks “Sign Out” on the /profile page: navigate(“/”) is called. dispatch(logout()) is … Read more
Summary This postmortem article discusses two Python programs that were written to solve specific problems, but contained errors that led to their failure. The first program was designed to read strings from a file and write to an output file all strings that appear as a substring of at least one other string in the … Read more
Summary A junior developer needed to extract the maximum score for a specific student from a CSV file, along with the corresponding subject. The standard approach using pandas (loading the entire dataset into memory) works for small files but introduces unnecessary overhead and potential memory saturation for large datasets. A more senior-engineer approach utilizes Python’s … Read more
Summary The question revolves around the behavior of lazy-loading images in HTML, specifically when an image is set to display:none by CSS and has a loading=”lazy” attribute. The goal is to understand whether such an image will be loaded with the page, and if the positioning on the page affects this behavior. Root Cause The … Read more
Summary The user is struggling to create a Straight Table in Qlik with three columns: current month sales, previous year sales for the same month, and a formatted date. The user attempted to use complex Set Analysis modifications to manually shift the selection context, which resulted in zero values or errors. The core issue is … Read more
Summary The batch tee function fails to handle raw binary byte streams correctly, resulting in data corruption where ASCII characters are replaced by garbled output (e.g., “Hello World” becomes “效汬潗汲”). The root cause is a mismatch between the input encoding and the batch processing logic. The input stream is likely UTF-16 encoded (standard output from … Read more