博客

求解一元一次方程，如10 x- 2 x= x + 12

#!/usr/bin/python
# -*- coding: UTF-8 -*-
# 解一元一次方程 
def solve(eq, var='x'):
    eq1 = eq.replace("=", "-(")+")"
    eq1 = eq1.replace("x", "*x")
    eq1 = eq1.replace("+*x", "+x")
    eq1 = eq1.replace("-*x", "-x")
    eq1 = eq1.replace("(*x", "(x")
    #print(eq1)
    c = eval(eq1, {var: 1j})
    return -c.real/c.imag

#test = "10 x- 2 x= x + 12"
test = raw_input('Input a euqation:\n')
#去除空格
test = test.replace(" ", "") 
print('The answer is', solve(test))

求解二元一次方程组，如2 x- 3y=10;3x= 5y-10

#!/usr/bin/python
# -*- coding: UTF-8 -*-
import sympy as sp
def transform(eq, var='x', var1='y'):
    eq1 = eq.replace("=", "-(")+")"
    eq1 = eq1.replace("x", "*x")
    eq1 = eq1.replace("+*x", "+x")
    eq1 = eq1.replace("-*x", "-x")
    eq1 = eq1.replace("(*x", "(x")
    eq1 = eq1.replace("y", "*y")
    eq1 = eq1.replace("+*y", "+y")
    eq1 = eq1.replace("-*y", "-y")
    eq1 = eq1.replace("(*y", "(y")
    return eq1

test1 = raw_input('Input the first euqation:\n')
test2 = raw_input('Input the second euqation:\n')
test1 = test1.replace(" ", "")
test2 = test2.replace(" ", "")
# 符号化变量
#x = sp.Symbol('x')  
x, y = sp.symbols('x y')
print sp.solve([transform(test1), transform(test2)], [x, y])