from sympy import *
init_printing()

x = symbols('x')

type(x)

sympy.core.symbol.Symbol

x**2

$$x^{2}$$

x,y = symbols('x,y')

(x+y)**2

$$\left(x + y\right)^{2}$$

expand((x+y)**2)

$$x^{2} + 2 x y + y^{2}$$

w = x**2 + 3*x + 6

w

$$x^{2} + 3 x + 6$$

diff(w,x)

$$2 x + 3$$

integrate(w,x)

$$\frac{x^{3}}{3} + \frac{3 x^{2}}{2} + 6 x$$

integrate(w,(x,0,4))

$$\frac{208}{3}$$

y = sin(x)

diff(y,x)

$$\cos{\left (x \right )}$$

See lambdify for conveting sympy expressions to numpy-friendly functions

OO programming

from numpy import *

class segment:
    
    # constructor
    def __init__(self, point,direction,length):
        self.p = array(point,dtype=float)
        self.u = array(direction,dtype=float)
        self.u /= linalg.norm(self.u)
        self.l = length
        
    def __repr__(self):
        #return 'Wow! My basepoint is ' + str(self.p)        
        return '('+str(self.p)+','+str(self.u)+','+str(self.l)+')'
        #return 'Wow! My basepoint is ' + str(self.p)

s = segment([3,4],[1.2,4],7)

print(s)

([ 3.  4.],[ 0.28734789  0.95782629],7)

class interface(segment):
    def __init__(self,point,direction,length,refindexL,refindexR):
        segment.__init__(self,point,direction,length)
        self.nL = refindexL
        self.nR = refindexR
    def __repr__(self):
        return 'Hahaha'

i = interface([0,0],[1,1],7,1.3,1.5)
i

Hahaha