15. Examen extraordinario (2016)¶

def imprimir_hex(n):
    top(n)
    for i in range(n-1):
        upper(n,i)
    for i in range(n-1):
        lower(n,i)
    bottom(n)

def top(n):
    print ' '*n + '_'*n
    print ' '*(n-1) + '/' + ' '*n + '\\'

def bottom(n):
    print ' '*(n-1) + '\\' + '_'*n + '/'

def upper(n, i):
    print ' '*(n-2-i) + '/' + ' '*(n+2+2*i) + '\\'

def lower(n, i):
    print ' '*i + '\\' + ' '*(n + 2*(n-i-1)) + '/'

imprimir_hex(4)
imprimir_hex(3)
imprimir_hex(2)

def frequent_browsers(path):
    with open(path,'r') as f:
        return [ x for x in browsers(f) if x[1] > 5. ]

def browsers(f):
    count = {}
    for linea in f:
        sid = extract_browser(linea)
        if sid in count:
            count[sid] += 1
        else:
            count[sid] = 1
    total = sum([count[x] for x in count])
    return sorted([ (x, 100.*count[x]/total) for x in count ],
                  key = lambda x: x[1], reverse=True)

def extract_browser(l):
    return l.split('"')[5]

frequent_browsers('access.log')

from math import sqrt, log, ceil

def butterworth(Hp,Ha,Wp,Wa):
    n = orden(Hp,Ha,Wp,Wa)
    Wc = fcorte(n, Hp, Wp)
    return (n, Wc)

def orden(Hp,Ha,Wp,Wa):
    Kd = sqrt((1./Hp**2 - 1)/(1./Ha**2 - 1))
    Ks = float(Wp) / Wa
    n = log(Kd)/log(Ks)
    return int(ceil(n))

def fcorte(n, Hp, Wp):
    return Wp/((1./Hp**2 - 1)**(1./(2*n)))

print butterworth(0.9, 0.1, 1e4, 1.1e4)

def pi_leibniz(n):
    suma = 0.
    for i in range(n):
        termino = 1./(2*i + 1)
        suma += termino if i%2 == 0 else -termino
    return 4.*suma

print pi_leibniz(100000)

def mediana(values):
    v = sorted(values)
    l = len(values)
    if l % 2 == 0:
        return .5*(v[l/2 - 1] + v[l/2])
    return v[l/2]

print mediana(range(9))
print mediana(range(10))

def validar_tarjeta(n):
    d = [int(x) for x in n]
    for i in range(0,16,2):
        d[i] *= 2
        if d[i] > 9:
            d[i] -= 9
    return sum(d) % (d[15] if d[15] else 10) == 0

print validar_tarjeta('4506252639731006')
print validar_tarjeta('4578463073273942')