I Traced 1000 Lines of Python Without Running It. Here Is What I Learned. (opens in new tab)

I spent three weeks doing nothing but Python code tracing. No IDE. No terminal. Just reading code and writing predicted outputs by hand. Here is what changed. Week 1 —> Everything Was Harder Than Expected I started with what I thought were easy problems. Simple for loops, basic string operations. I got roughly 55 percent right. The failures were not random. They clustered around the same concepts every time. Negative indexing. I kept miscounting from the end of sequences. The difference betwe...