Python Functions in Depth

What you will learn

• Default and keyword arguments
• Guard clauses and return values
• *args and **kwargs
• Scope and LEGB
• Lambdas and key functions
• map, filter and generators
• Closures
• Decorators
• Recursion

Lessons

1. 1

   Parameters and Arguments

   Call functions by position or by name, give parameters defaults, return early on purpose, and dodge the mutable default trap.

   11 exercises

2. 2

   Flexible Signatures

   Accept any number of arguments with *args and **kwargs, force keywords, and unpack at the call site.

   12 exercises

3. 3

   Scope

   Know which variable a name refers to, avoid UnboundLocalError and shadowed built-ins, and prefer return values over globals.

   12 exercises

4. 4

   Functions Are Values

   Pass functions around, return them, write lambdas, sort, filter and map with them, and write a generator with yield.

   14 exercises

5. 5

   Closures and Decorators

   Keep private state inside a function with closures, then wrap functions with decorators that clamp, count, retry and guard.

   12 exercises

6. 6

   Recursion and Putting It Together

   Solve nested problems with recursion and a base case, then build a discount pipeline, a memoize decorator and an event dispatcher.

   10 exercises

How you practice

You practice in the browser and every exercise gives you feedback right away. This course uses these formats:

• Code exercise: 27
• Fix the bug: 14
• Predict the output: 8
• Multiple choice: 7
• Fill in the blank: 7
• Type the answer: 4
• Match the pairs: 1
• Spot the bug: 1
• Select all that apply: 1
• Reorder lines: 1

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