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@alcides

alcides/poly6.py Secret

Last active Mar 29, 2017
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class Poly(object):
def __init__(self, coef_initial=0, exponent_initial = 0, coefs=None):
""" Create a polynomial with exactly one term, with coefficient
coeff and exponent exponent, where coeff is an integer and exponent is a non-negative integer
Defaults to the polynomial zero """
if coefs == None:
# if coeff == 0, then exponent should be 0
if coef_initial == 0:
exponent_initial = 0
self.coefs = ([0]*exponent_initial)
self.coefs.append(coef_initial)
else:
self.coefs = coefs
"""
Permite criar o Poly de duas maneiras:\
Poly(coef_initial=5, exponent_initial=3) - [0,0,0,5]
Poly(coefs=[0,1,2,3]) - [0,1,2,3]
"""
def format1(self, c, e):
if e != 0:
f = "{}x^{}".format(c,e)
else:
f = str(c)
return f
def __str__(self):
# [7, 0, -5, 0, 3]
s = ""
for exp, c in list(enumerate(self.coefs))[::-1]:
if c != 0:
if exp == 0:
s += str(c) + " + "
else:
s += str(c) + "x^" + str(exp) + " + "
return s[:-2] #" 3x^4 + -5x^2 + 7 "
""" Alternativa """
return " + ".join([ self.format1(c,e) for e,c in enumerate(self.coefs) if c != 0 ][::-1])
def isZero(self):
""" Devolve se o polinomio e igual ao polinomio zero """
return all([i == 0 for i in self.coefs])
def coeff(self, exp=0):
# p.coefs = [1,0,5,0,2,7]
# p.coeff[4] = 2
if exp >= len(self.coefs):
return 0
else:
return self.coefs[exp]
"Alternativa:"
"""
try:
return self.coefs[exp]
except:
return 0
"""
def degree(self):
v = len(self.coefs)-1
ultimoIndice = v
while self.coefs[ultimoIndice] == 0 and ultimoIndice > 0:
v -= 1
ultimoIndice -= 1
return v
def __add__(self, o):
lg = self.coefs
lp = o.coefs
if len(lg) < len(lp):
lg, lp = lp, lg
nv = [ i for i in lg ]
for i, v in enumerate(lp):
nv[i] += v
return Poly(coefs=nv)
"""
# Alternativa
ma = max(len(self.coefs), len(o.coefs))
nl = []
for i in range(ma):
v = 0
if i < len(self.coefs):
v += self.coefs[i]
if i < len(o.coefs):
v += o.coefs[i]
nl.append( v )
# Preeencher poly
# Alternativa com map
def f(a,b):
if a == None:
return b
if b == None:
return a
return a+b
nv = map(f, self.coefs, o.coefs)
# Preeencher poly
"""
def minus(self):
nv = [ -e for e in self.coefs ]
return Poly(coefs=nv)
def __sub__(self, o):
return self + o.minus()
def __mul__(self, o):
p = Poly()
for e1, c1 in enumerate(self.coefs):
for e2, c2 in enumerate(o.coefs):
p = p + Poly(coef_initial=c1*c2, exp_initial=e1+e2)
return p
def evaluate(self, x):
v = 0
for e, c in enumerate(self.coefs):
v += c * x**e
return v
#print Poly(5,4) + Poly(3,2) # deve devolver - Poly.coefs = [0,0,3,0,5]
#print Poly(coefs=[0,0,1,0,5]).minus() # [0,0,1,0,5] -> [0,0,-1,0,-5]
print Poly(5,4) - Poly(3,2) # deve devolver - Poly.coefs = [0,0,-3,0,5]
"""
def testa(p):
print "str():", str(p)
print "isZero():", p.isZero()
print "coeff(4):", p.coeff(4)
print "degree():", p.degree()
print "----"
testa(Poly(coef_initial=0, exponent_initial=0))
testa(Poly(coef_initial=5, exponent_initial=4))
p = Poly(coef_initial=5, exponent_initial=4)
p.coefs = [1,0,5,0,2,7] # BATOTA!!!!!!!!!!!!!!
testa(p)
p_ = Poly(coef_initial=5, exponent_initial=4)
p_.coefs = [0,0,0,0,0,0]
testa(p_)
p_2 = Poly(coef_initial=5, exponent_initial=4)
p_2.coefs = [1,0,0,0,0,0]
testa(p_2)
"""
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