Inspect
Meet a table, find your way around it, and ask your first useful questions.
01 / Getting oriented
Meet a DataFrame
Build a small table from named columns.
8 min · 3 practicesTake the first look
Look at a few rows before making assumptions.
8 min · 3 practicesLoad a CSV
Load a file and inspect what arrived.
8 min · 3 practicesHow big is it?
Read the row and column counts.
8 min · 3 practicesWhat columns arrived?
Find the exact column and row labels.
8 min · 3 practicesWhat types are these?
Distinguish numeric columns from text.
8 min · 3 practicesReview · First contact
Retrieve earlier skills on a fresh table.
12 min · 4 retrieval tasks02 / Selecting data
Pick one column
Select one named column as a Series.
8 min · 3 practicesPick several columns
Keep a two-dimensional table of selected columns.
8 min · 3 practicesRows by position
Select rows using their zero-based positions.
8 min · 3 practicesRows and columns by label
Select named rows and columns with loc.
8 min · 3 practicesFilter rows
Keep rows where a condition is true.
8 min · 3 practicesCombine conditions
Combine row tests without losing their meaning.
8 min · 3 practicesReview · Select with intent
Retrieve earlier skills on a fresh table.
12 min · 3 retrieval tasks03 / Understanding values
Sort the table
Order filtered rows to answer a question.
8 min · 3 practicesFind extremes
Ask for the largest or smallest observations.
8 min · 3 practicesWhat values exist?
Find distinct category values.
8 min · 3 practicesCount categories
Compare category frequencies and proportions.
8 min · 3 practicesFind missing values
Locate gaps before summarising.
8 min · 3 practicesFind duplicate rows
Count repeated records without removing anything.
8 min · 3 practicesReview · Find the surprises
Retrieve earlier skills on a fresh table.
12 min · 4 retrieval tasks04 / Reading the whole table
Describe numeric columns
Read a compact numerical profile.
8 min · 3 practicesAnswer one numerical question
Choose a direct summary for a specific question.
8 min · 3 practicesSummarise groups
Compare a simple average across categories.
8 min · 3 practicesCompare categories
Count combinations of two categories.
8 min · 3 practicesInspect numeric relationships
Read correlation as association, not causation.
8 min · 3 practicesInspect checkpoint
Profile an unfamiliar eight-row table from scratch.
15 min · 3 retrieval tasks