[Edu-sig] pythonic andragogy...

[kirby urner]

Below is a transcript of my first Python training session with a
friend from Jordan, Arabic speaking but completely fluent in English
(knows QWERTY touch type better).  She has PhD and previous
programming experience in a much earlier job, so this is hardly a high
school student.  And yet I start my introduction in much the same way,
using my "objects first" approach (not unlike AlgebraFirst in some
math circles).

As I was writing to a prominent Python teacher the other day:

"""

In an "objects first" mindset, we run like hell from the CS1/CS2
tendency to look at objects as "2nd year advance topic" i.e. we'll
gradually slog through data structures, procedural programming, flow
of control, conditions, types, type coercion... and then spring
"objects" on ya as a Grand Unified Theory (like now we're ready for
Einstein level Python).

No, no and no.

The OO revolution was about making programming easier *from the top*
i.e. we're taking everyday commonsense about "things with attributes
and behaviors" and expressing those directly.

So you need to *start* by explaining what Python being an object
oriented language means, by starting with very simple Foo and Bar
classes, or better Biotum, Dog, Monkey, then subclass as mammal.

This counts as a preview or trailer (to a film), enrolls the student
in the idea that (a) hey, I'm learning what OO means at last and (b)
hey, thinking this way is really natural after a bit.

Because once we've done the work to show a user defined type, then we
have the concept of type (type of object).  That then anchors the
whole discussion of native or __builtin__ types e.g. now that you've
seen a Biotum, a Python (everything is a python in python), it's
really natural to see List type, Vector type (non-native), Integer
type as "just more creatures with __ribs__."
"""

We switched the keyboard back and forth.

Like when she tries to feed the snake both a carrot and some beer,
that crashes because the args don't match, but even though I warned
her, she wanted to see the error message anyway.

Our venue with Powell's Technical, Personal Telco node for Wifi:
http://www.personaltelco.net/
http://www.powells.com/technicalbooks

We also talked a lot about micro-lending to women i.e. would there be
any overlap between Python skills and a small business managed by
women?  I'll have more about that aspect in my blogs.  I need to
connect her to Idealist.org -- maybe through PPUG, where several from
that organization have leadership roles.

Transcript follows:

Python 3.1.1 (r311:74483, Aug 17 2009, 17:02:12) [MSC v.1500 32 bit
(Intel)] on win32
Type "copyright", "credits" or "license()" for more information.
>>> class Snake:
    def __init__(self, name):
        self.me = name


>>> kirby_snake = Snake("Kirby Urner")
>>> kirby_snake.me
'Kirby Urner'
>>> 2 ** 10000
19950631168807583848837421626835850838234968318861924548520089498529438830221946631919961684036194597899331129423209124271556491349413781117593785932096323957855730046793794526765246551266059895520550086918193311542508608460618104685509074866089624888090489894838009253941633257850621568309473902556912388065225096643874441046759871626985453222868538161694315775629640762836880760732228535091641476183956381458969463899410840960536267821064621427333394036525565649530603142680234969400335934316651459297773279665775606172582031407994198179607378245683762280037302885487251900834464581454650557929601414833921615734588139257095379769119277800826957735674444123062018757836325502728323789270710373802866393031428133241401624195671690574061419654342324638801248856147305207431992259611796250130992860241708340807605932320161268492288496255841312844061536738951487114256315111089745514203313820202931640957596464756010405845841566072044962867016515061920631004186422275908670900574606417856951911456055068251250406007519842261898059237118054444788072906395242548339221982707404473162376760846613033778706039803413197133493654622700563169937455508241780972810983291314403571877524768509857276937926433221599399876886660808368837838027643282775172273657572744784112294389733810861607423253291974813120197604178281965697475898164531258434135959862784130128185406283476649088690521047580882615823961985770122407044330583075869039319604603404973156583208672105913300903752823415539745394397715257455290510212310947321610753474825740775273986348298498340756937955646638621874569499279016572103701364433135817214311791398222983845847334440270964182851005072927748364550578634501100852987812389473928699540834346158807043959118985815145779177143619698728131459483783202081474982171858011389071228250905826817436220577475921417653715687725614904582904992461028630081535583308130101987675856234343538955409175623400844887526162643568648833519463720377293240094456246923254350400678027273837755376406726898636241037491410966718557050759098100246789880178271925953381282421954028302759408448955014676668389697996886241636313376393903373455801407636741877711055384225739499110186468219696581651485130494222369947714763069155468217682876200362777257723781365331611196811280792669481887201298643660768551639860534602297871557517947385246369446923087894265948217008051120322365496288169035739121368338393591756418733850510970271613915439590991598154654417336311656936031122249937969999226781732358023111862644575299135758175008199839236284615249881088960232244362173771618086357015468484058622329792853875623486556440536962622018963571028812361567512543338303270029097668650568557157505516727518899194129711337690149916181315171544007728650573189557450920330185304847113818315407324053319038462084036421763703911550639789000742853672196280903477974533320468368795868580237952218629120080742819551317948157624448298518461509704888027274721574688131594750409732115080498190455803416826949787141316063210686391511681774304792596709376
>>>
>>>
>>>
>>> class Snake:
    def __init__(self, name):
        self.me = name
        self.stomach = []
    def eat(self, food):
        self.stomach.append(food)
    def __repr__(self):
        return "Snake(%s)" %

SyntaxError: invalid syntax (<pyshell#16>, line 8)
>>> class Snake:
    def __init__(self, name):
        self.me = name
        self.stomach = []
    def eat(self, food):
        self.stomach.append(food)
    def __repr__(self):
        return "Snake(%s)" % self.me


>>> tag = Snake("Dr. Tag")
>>> tag
Snake(Dr. Tag)
>>> snake2 = Snake("Kirby")
>>> snake2
Snake(Kirby)
>>> snake2.eat("beer")
>>> snake2.stomach
['beer']
>>> snake2.eat("carrot")
>>> snake2.stomach
['beer', 'carrot']
>>> tag.stomach
[]
>>> tag.eat("carrot","beer")
Traceback (most recent call last):
  File "<pyshell#28>", line 1, in <module>
    tag.eat("carrot","beer")
TypeError: eat() takes exactly 2 positional arguments (3 given)
>>> a = []
>>> a
[]
>>> a.append(2)
>>> a
[2]
>>> a.append(8)
>>> a
[2, 8]
>>> a.append("the wonderful food of the day")
>>> a
[2, 8, 'the wonderful food of the day']
>>> a.pop(0)
2
>>> a
[8, 'the wonderful food of the day']
>>> tag.stomach
[]
>>> tag.eat("carrot")
>>> tag.eat("beer")
>>> tag.stomach
['carrot', 'beer']
>>> tag.stomach("hummus")
Traceback (most recent call last):
  File "<pyshell#43>", line 1, in <module>
    tag.stomach("hummus")
TypeError: 'list' object is not callable
>>> tag.eat("hummus")
>>> tag.stomach
['carrot', 'beer', 'hummus']
>>> snake2.stomach
['beer', 'carrot']
>>> class Snake:
    def __init__(self, name):
        self.me = name
        self.stomach = []
    def eat(self, food):
        self.stomach.append(food)
    def poop(self):
        if len(self.stomach) > 0:
            return self.stomach.pop(0)
    def __repr__(self):
        return "Snake(%s)" % self.me


>>> newsnake = Snake("Kirby")
>>> newsnake.stomach
[]
>>> newsnake.poop()
>>> newsnake.eat("something yummy")
>>> newsnake.stomach
['something yummy']
>>> newsnake.poop()
'something yummy'
>>> newsnake.stomach
[]
>>>
"""

Note that I didn't get into my uroboros thing with the self-eating
Python, per Vilnius slides (EuroPython 2007).

Kirby