python - NameError:名称 'first' 未定义

Question

我是Python新手，我正在尝试绘制函数图。这是我的代码:

class Optic():
    def __init__(self):
        '''
        param define
        '''
        global time,lamda, light_speed, Fc, D, z, beta, T0
        self.__time = np.linspace(-400,400, 1600) #Picosec
        self.__lamda = 1550000 #Picometer
        self.__light_speed = 0.3 #meter/Picosec
        self.__Fc=light_speed/lamda #Hz
        self.__D = 17*np.power(10,-6) #sec/meter
        self.__z=[0,10000,20000,30000] #meter
        self.__beta = (-(np.power(lamda,2)/(2*np.pi*light_speed))*D) #sec/meter
        self.__T0 = 200
#        time = np.linspace(-400*np.power(10,-12), 0.5*np.power(10,-12), 400*np.power(10,-12)) #sec
#        lamda = 1550*np.power(10,-9) #meter
#        light_speed = 3*np.power(10,8) #sec/meter
#        Fc=light_speed/lamda #Hz
#        D = 17*np.power(10,-6) #sec/meter
#        z=[0,10000,20000,30000] #meter
#        beta = (-(np.power(lamda,2)/(2*np.pi*light_speed))*D) #sec/meter
#        T0 = 20*np.power(10,-12)

    def firstPulse(self):
        global first
        first = np.exp(-0.5*np.power(time/T0,2))

def main():
    plt.plot(first, time)
    plt.show()


if (__name__ == "__main__"): 
    main()

但我得到:

NameError: name 'first' is not defined

顺便说一句，我正在使用 Spyder。

Answer 1

您已初始化 Optic 并调用定义该变量的 def firstPulse(self)。

类似这样的事情:

def main():
    opt = Optic():
    opt.firstPulse()
    plt.plot(first, time)
    plt.show()