多项式（4）* x ** 3 +（2 * a）* x ** 2 +（b-3）* x +（-a）==> 4 * x ** 3 + 2 * a * x ** 2 +（b-3）* xa？howto

Question

提前感谢您，英语不好！

正则表达式？

（ref）

抱歉日本

https://ja.stackoverflow.com/questions/33677/sympy%e3%81%aecoeff%e3%81%ae%e4%bd%bf

from sympy import *
var('x a b')
def MyCoeff(myf, i):
    if i==0 :
    p = Poly(f, x)
   MyCoeff = p.coeff_monomial(0+1)
   else:
   MyCoeff = myf.coeff(x ** i)
   return MyCoeff
f=4*x**3 + 2*a*x**2 + (b-3)*x -a
print(f)
print(""("",MyCoeff(f, 3),"")*x**3+"","
      ""("",MyCoeff(f, 2),"")*x**2+"","
      ""("",MyCoeff(f, 1),"")*x+"","
      ""("",MyCoeff(f, 0),"")"""
)
# 2*a*x**2 - a + 4*x**3 + x*(b - 3)
# ( 4 )*x**3+ ( 2*a )*x**2+ ( b - 3 )*x+ ( -a )

Answer 1

>>> f=4*x**3 + 2*a*x**2 + (b-3)*x -a
>>> Poly(f, x).all_coeffs()
[4, 2*a, b - 3, -a]