Welcome to MadPy!

Organizers

Ed Rogers	David Hoese	Josh Karpel

Code of Conduct

MadPy is a community group and open to all experience levels. We are committed to a safe, professional environment

Our Commitment to You

We are enthusiastically focused on improving our event and making it a place that is welcoming to all. All reports will be taken seriously, handled respectfully, and dealt with in a timely manner.

Learn more about the MadPy Code of Conduct:

https://github.com/madison-python/code-of-conduct

Python Warm-Up

Calling Yield Multiple Times

def some_things():
    yield 1
    yield 2
    yield 3

def them():
    for thing in some_things():
        yield thing

What happens when we call list(them())?

list(them())

[1, 2, 3]

Changing them() to return a list instead of a generator

def some_things_as_a_list():
    return list(some_things())

def them():
    return some_things_as_a_list()  # Using return
                                    # instead of the yield call
    for thing in some_things():
        yield thing

What will list(them()) return?

list(them())

[]

Taking a closer look at them()

def them():
    return some_things_as_a_list()
    # for thing in some_things():
    #     yield thing

list(them())

[1, 2, 3]

Because yield appears in the function body, Python compiles them as a generator function — at compile time, before any code runs.

Calling them() returns a generator object without executing anything. The return value is silently ignored during iteration.

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