Key point
Main idea
Your job is not to make pandas run. Your job is to make messy data safe enough to trust.
Most project bugs come from wrong types, missing values, duplicate rows, broken dates, mixed spellings, and tables that do not join cleanly.
Why it takes time
Real data is collected by forms, apps, admins, vendors, sensors, and people in a hurry. A college event sheet may have “CSE”, “cse”, “Computer Science”, and blank department values in the same column.
pandas is used because it works well with tables. A table in pandas is called a DataFrame. You use it to load, explore, clean, process, join, group, and write data.