Porque aprender haskell me fez um programador python melhor?

Porque aprender haskell me fez um programador

python melhor?

@[email protected]


python melhor?

@[email protected]

Baseado em fatos reais

Gustavo Pinto

2004 - belém, grad, php, sh2006 - amazontic, java, xp2008 - curitiba, msc, python2009 - aprioriti, xp, scrum2011 - recife, phd, haskell2012 - entropie, lean, scala

Belém

DISCLAIMER

Não tem código

Não tem código¬¬''

Mentira, tem mas épouquinho :-)

1912 ~ 1954

1912 ~ 19541936

ON COMPUTABLE NUMBERS, WITH AN APPLICATION

TO THE ENTSCHEIDUNGS

PROBLEM

ON COMPUTABLE NUMBERS, WITH AN APPLICATION

TO THE DECISION PROBLEM

1903 ~1995

1903 ~19951936

AN UNSOLVABLE PROBLEM OF ELEMENTARY

NUMBER THEORY

Church-Turing thesis

Church-Turing thesis

Equivalentes

Algumas features:

● Pure functions● Functions as first-class objects● No side effects

Algumas features:

● Pure functions● Functions as first-class objects● No side effects

Concurrency Friendly

Great.. But, what about Python??

Python functional

Is python functional?

I have never considered Python to be heavily influenced by functional

languages, no matter what people say or think. I was much more familiar with imperative languages such as C and

Algol 68 and although I had made functions first-class objects, I didn't view

Python as a functional programming language. However, earlier on, it was

clear that users wanted to do much more with lists and functions.

http://python-history.blogspot.com.br/2009/04/origins-of-pythons-functional-features.html



I see list and functions

hack, hack

if god exists: atepassar**2

search_list = lambda l,e : [ [ idx for idx, element in enumerate(l) if element ==

element_f ] for element_f in e]

List comprehensionA basic comprehension for a set that contains the first ten even natural numbers is

The part before the pipe is called the output function, x is the variable, N is the input set and x <= 10 is the predicate. That means that the set contains the doubles of all natural numbers that satisfy the predicate.

http://learnyouahaskell.com/starting-out#im-a-list-comprehension




>>> [i for x in range (0, 100) if x > 10]





>>> [i for x in range (0, 100) if x > 10]>>> [[row[i] for row in matrix] for i in range(4)]





>>> [i for x in range (0, 100) if x > 10]>>> [[row[i] for row in matrix] for i in range(4)]>>> dict([(i, chr(65+i)) for i in range(4)])





>>> [i for x in range (0, 100) if x > 10]>>> [[row[i] for row in matrix] for i in range(4)]>>> dict([(i, chr(65+i)) for i in range(4)])


Sou foda



LambdaLambdas are basically anonymous functions that are used because we need some functions only once. Normally, we make a lambda with the sole purpose of passing it to a higher-order function.

http://learnyouahaskell.com/higher-order-functions#lambdas



Lambda>>> lambda x: x % 2




Lambda>>> is_even = lambda x: x % 2




Lambda>>> is_even = lambda x: x % 2>>> is_even<function <lambda> at 0x2a3d050>




Built-in Functions>>> for mes in enumerate (['jan', 'fev', 'mar']):... print mes(0, 'jan')(1, 'fev')(2, 'mar')


outras built-in functions: ● filter● map● reduce


outras built-in functions: ● filter● map● reduce

Funções de alta ordem

Filterfilter(...)

filter(function or None, sequence) -> list, tuple or string

Return those items of sequence for which function(item) is true. [....]

>>> filter(lambda x: x % 2 == 0, range(10))

Filterfilter(...)

filter(function or None, sequence) -> list, tuple or string

Return those items of sequence for which function(item) is true. [....]

>>> is_even = lambda x: x % 2 == 0>>> filter(is_even, range(10))

Mapmap(...)

map(function, sequence[, sequence, ...]) -> list

Return a list of the results of applying the function to the items of the argument sequence(s). [....]

>>> map(lambda s: s.upper(), ['a', 'b', 'c'])

Reducereduce(...)

reduce(function, sequence[, initial]) -> value

Apply a function of two arguments cumulatively to the items of a sequence, from left to right, so as to reduce the sequence to a single value. [....]

>>> reduce(lambda x,y: x * y, range(1, 4))>>> reduce(lambda x, y: x + y, ['a', 'b', 'c', 'd'])

Sua High Order Functiondef f(x):

return x + 1

def g(function, x):return function(x) + function (x + 1)

print g(f, 1)

Sua High Order Functiondef f(x):

return x + 1

def g(function, x):return function(x) + function (x + 1)

print g(f, 1)

not bad


python melhor?

Consegui entendermelhor o

código do Marcel!

Consegui entender melhor o código

de outras pessoas!

Consegui entender melhor a minha

linguagem!

Consegui entender melhor o meu

framework!

Resumindo

Domine sua linguagem

Evolua com a sua linguagem

Domine outras linguagens(Tanto quanto)

Entenda que linguagens são

escolhas

Seja o principal crítico das suas

escolhas

Para saber mais:

from functional import *

OBRIGADO!

@[email protected]

Porque aprender haskell me fez um programador python melhor?

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