Higher Order Functions with Python - sorted/map/filter/reduce and friends

A quick overview for students in my online class: higher order functions are functions that take and return values which happen to be functions. In order to sort things in Python you need to know about key-functions which you pass to the builtin sorted - but you might also check out map, filter, reduce, min, max and so on. You can also use functional closures to produce custom functions from functions - and understanding this concept can lead to all sorts of interesting techniques.

[HenockTesfaye]

My face just lit up!
"I see clearly now"
Thank you for an excellent tutorial.

[IAMZERG]

Thank-you, sir! you just saved me oodles of time. If only I'd seen this sooner.

[__nicfit__]

In Python 3.x reduce is part of functools. import functools; functools.reduce(...)

[SimeonFranklin]

Good point! I'm teaching a class on 2.7 so I didn't think to mention it...

[Pterryreal]

Hey, nice tutorial, but the last thing I didn't get. Why I need the closure for sorting if I could use a simple lambda or function instead?
sorted(["howard", "ray", "sheldon", "lenard"], key: lambda x: x[-2])
Is there an example of closures where I really need use them instead of alternative ways?

[sidzie]

Thank you for this wonderful video and your time..great job!