The query() Method

The query() method provides a SQL-like syntax for filtering DataFrames. It's often more readable than boolean indexing.

Basic Query Syntax

Write conditions as strings:

Comparison with Boolean Indexing

Compare readability:

Using Variables in Queries

Reference Python variables with @:

Complex Queries

Combine conditions with and, or, not:

Query with in and not in

Check membership in lists:

String Methods in Query

Use string methods with .str:

Exercise: Simple Query

Exercise: Query with Variable

Key Points

• query() uses string expressions for filtering
• More readable than boolean indexing
• Use @variable to reference Python variables
• Use and, or, not instead of &, |, ~
• Use in and not in for membership checks
• For string methods, stick with .str accessor