fcts.py 文件源码

def inverse_eqn(eqn):
    """
    Inverse a symbolic expression with variable x
    Keeps x as the variable in the inverted expression
    > inverse('4*x/2')
    'y = x/2'
    """
    e = sympify('-x + ' + eqn.replace('x', 'y'))
    return str(solve(e, 'y')[0]).replace('x', 'float(x)')