Fizz and Buzz of

Computer Programsin Python.

esehara shigeo

WHOARE

YOU?

Shigeo Esehara Just a Programmer using Python

andLove Trivial Programming

!! WARNING !!I guess you get used to my funny English Speaking.

(or Programming ?)

OK. Ready!!

GO!!

Before,Programmers had

“The Common Sense”...

SICP

But….

Jeff Atword(ex-StackOverFlow)

wrote the essay:Why Can't Programmers..

Program?

Then….

Now,Programmer has

“The Common Sense”...

FIZZ

BUZZ

FizzBuzz Rule● Write a program that prints the

numbers from 1 to 100. ● For multiples of three print “Fizz”

instead of the number● For multiples of five print “Buzz”.● For numbers which are multiples of

both three and five print “FizzBuzz”

Other Lang Example

Haskell :: Maybe Monads FizzBuzztype IsFizzBuzz = Maybe String is_n:: Integer -> Integer -> Integeris_n x y = x `mod` y fizz :: Integer -> Integerfizz x = is_n x 3 buzz :: Integer -> Integerbuzz x = is_n x 5 maybe_div :: Integer -> String -> IsFizzBuzz -> IsFizzBuzzmaybe_div 0 str m = case m of Nothing -> Just str Just x -> Just $ str ++ xmaybe_div _ str m = m maybe_fizz :: Integer -> IsFizzBuzz -> IsFizzBuzzmaybe_fizz x m = maybe_div is_fizz "Fizz" m where is_fizz = fizz x

maybe_buzz :: Integer -> IsFizzBuzz -> IsFizzBuzzmaybe_buzz x m = maybe_div is_buzz "Buzz" m where is_buzz = buzz x maybe_fizzbuzz :: Integer -> IsFizzBuzz -> Stringmaybe_fizzbuzz x m = case m of Nothing -> show x Just x -> x maybe_process :: Integer -> Stringmaybe_process x = maybe_fizzbuzz x =<< is_fizzbuzz x where is_fizzbuzz x = maybe_fizz x >>= maybe_buzz x

go :: (Integer -> String) -> IO ()go f = process f 1

process :: (Integer -> String) -> Integer -> IO ()process f 101 = putStr ""process f x = (putStrLn $ f x) >> process f next where next = x + 1

OK.

Real Pythonista

solvesthe Problem at 3sec.

Basic

# begin codefor i in range(1, 100): if (i % 15 == 0): print "FizzBuzz" if (i % 3 == 0): print "Buzz" if (i % 5 == 0): print "Fizz" print i# end

“Are You kidding me ?”

No!!

Real Pythonistadon’t use “if”statementin FizzBuzz.

Hint

FizzBuzz Structureconsist

“Loop” and “Branch”.

In other words ...

“Loop”is

“Iteration”.

Iterator in Python ?

List.

3 of multiple explession:

[1, 2, 3, 4, 5, 6, 7, 8, 9 …]

Fizzlize!!

[‘’, ‘’, ‘Fizz’, ‘’, ‘’, ’Fizz’,‘’, ‘’, ’Fizz’

…]

More!!

[‘’, ‘’, ‘Fizz’] * 3List can be multipication in Python.

“Use type conversion, Luke.”

bool(‘’) = Falseint(False) = 0

not use “if” statements

fizz = ['', '', “Fizz”] * 50buzz = ['', '', '', '', “Buzz”] * 50

for x in range(1, 101): fizzbuzz = fizz[x] + buzz[x] number = str(x) * (not bool(fizzbuzz)) print fizzbuzz + number

“It seems bad because

it generates listlike *malloc*

in C language.”

oh...

Real Pythonistause “itertools”

in FizzBuzz.

Pythonista like ‘itertools’.

from itertools import cycle

fizz = cycle(['', '', 'Fizz'])buzz = cycle(['', '', '', '', '', 'Buzz'])

for i in range(1, 101): fizzbuzz = fizz.next() + buzz.next() fizzbuzz += (str(i) * (not bool(fizzbuzz))) print fizzbuzz

But...

TRUE Pythonistadon’t use *“List”

in FizzBuzz.* Strictly speaking,

“String” has “List”(= array (= char sets)) Structure, but now, String is exception.

Do you thinkit possible ?

Yes,

We Can !!

OK.

Hint

Loopcan be created

using “Recurtion”.

Recursion

def loop(start, limit): print start (start == limit) or loop(start + 1, limit)loop(1, 100)

FizzBuzz flag

Fizz, Buzz = [Bool, Bool]

FizzBuzz flag

Fizz, Buzz = [0 or 1, 0 or 1]

FizzBuzz flag

Number = [0, 0]Fizz = [1, 0]Buzz = [0, 1]

FizzBuzz = [1, 1]

“It seems likebinary system.”

Yes !! Binary System.

Number = 00 = 0Fizz = 01 = 1Buzz = 10 = 2

FizzBuzz = 11 = 3

Example :: PHP<?php function _00($i) { echo $i; } function _10($i) { echo "Fizz"; } function _01($i) { echo "Buzz"; } function _11($i) { echo _10($i); echo _01($i); }

for ($i = 1; $i < 101; $i++) { $fizz = $i % 3 === 0; $fizz = (int) $fizz; $fizz = (string) $fizz; $buzz = $i % 5 === 0; $buzz = (int) $buzz; $buzz = (string) $buzz; $fizzbuzz = "_" . $fizz . $buzz; $fizzbuzz($i); echo "\n";}

“Use the String, Luke.”

" FizzBuzzFizzBuzz"

“Use the String, Luke.”

" FizzBuzzFizzBuzz"[ 0 ][ 1 ][2 ][3 ]

* “FizzBuzz” is just only 8 string.

Imaginethere’sno list..

No List !!

def loop(start, limit): fizzbuzz = (not start % 3) | ((not start % 5) * 2) print (" FizzBuzz FizzBuzz"[ fizzbuzz * 4: (fizzbuzz + 1) * 4 + ((fizzbuzz == 3) * 4)].strip() ) or start (start == limit) or loop(start + 1, limit)loop(1, 100)

Congratulations!!

Thanks foryour attention.

twitter: @eseharagithub.com/esehara