Data in the wild is rarely perfect. Missing entries, corrupted records, and null values are the norm. As a data scientist, your first job is to identify these gaps and decide whether to drop them or fill them with intelligent estimates.
1Identifying the Gaps
Pandas provides isna() and isnull() to detect missing data. By chaining these with .sum(), you can quickly see which columns are the most problematic and require your attention.
2Drop or Fill?
You have two main strategies: dropping or imputing. dropna() is fast but loses information. fillna() allows you to replace gaps with zeros, means, or medians, preserving the rest of the row's data for analysis.
