Merging Dictionaries

Concepts: pyDictMerge

Combining two dictionaries into one is a common operation. Python provides several ways to do this, each with different trade-offs. Method 1: Using .update() Method 2: | Operator (3.9+) Modern Python (3.9 and later) introduced the | operator for merging dictionaries. This creates a NEW dictionary without modifying the originals: When both dictionaries have the same key, the value from the right-side dictionary (after the |) wins. This is intuitive: you're "applying" user preferences on top of defaults. Method 3: |= Operator Fill in the blanks to merge user preferences on top of defaults without modifying the original defaults dictionary. The defaults-plus-overrides pattern is ubiquitous in Python applications. Configuration systems, API clients, and testing frameworks all use it. A base di