使用turtle库、time库编程实现循环交替绘制当前时间和自己学号的七段数码管，即绘制七段数码管显示当前时间（时分秒），一秒后绘制七段数码管显示自己学号，不断循环。

以下是使用turtle库和time库实现循环交替绘制当前时间和自己学号的七段数码管的代码：

import turtle
import time

# 设置七段数码管的数字
digits = {
    0: [1, 1, 1, 0, 1, 1, 1],
    1: [0, 0, 1, 0, 0, 1, 0],
    2: [1, 0, 1, 1, 1, 0, 1],
    3: [1, 0, 1, 1, 0, 1, 1],
    4: [0, 1, 1, 1, 0, 1, 0],
    5: [1, 1, 0, 1, 0, 1, 1],
    6: [1, 1, 0, 1, 1, 1, 1],
    7: [1, 0, 1, 0, 0, 1, 0],
    8: [1, 1, 1, 1, 1, 1, 1],
    9: [1, 1, 1, 1, 0, 1, 1]
}

# 设置每个数码管的位置
positions = [
    [-200, 200],
    [-50, 200],
    [100, 200],
    [-200, 50],
    [-50, 50],
    [100, 50],
    [-75, -100]
]

# 绘制一个七段数码管
def draw_digit(position, digit):
    turtle.penup()
    turtle.goto(position)
    turtle.pendown()

    if digit[0]:
        turtle.forward(50)
    else:
        turtle.penup()
        turtle.forward(50)
        turtle.pendown()

    turtle.right(90)

    if digit[1]:
        turtle.forward(50)
    else:
        turtle.penup()
        turtle.forward(50)
        turtle.pendown()

    turtle.right(90)

    if digit[2]:
        turtle.forward(50)
    else:
        turtle.penup()
        turtle.forward(50)
        turtle.pendown()

    turtle.right(45)

    if digit[3]:
        turtle.forward(35.4)
    else:
        turtle.penup()
        turtle.forward(35.4)
        turtle.pendown()

    turtle.right(90)

    if digit[4]:
        turtle.forward(35.4)
    else:
        turtle.penup()
        turtle.forward(35.4)
        turtle.pendown()

    turtle.right(45)

    if digit[5]:
        turtle.forward(50)
    else:
        turtle.penup()
        turtle.forward(50)
        turtle.pendown()

    turtle.right(90)

    if digit[6]:
        turtle.forward(50)
    else:
        turtle.penup()
        turtle.forward(50)
        turtle.pendown()

    turtle.penup()

# 绘制当前时间的七段数码管
def draw_time():
    # 获取当前时间
    now = time.strftime("%H%M%S")

    # 绘制数字
    for i in range(len(now)):
        draw_digit(positions[i], digits[int(now[i])])

# 绘制学号的七段数码管
def draw_number():
    number = "2018111111"

    # 绘制数字
    for i in range(len(number)):
        draw_digit(positions[i], digits[int(number[i])])

# 设置画布大小
turtle.setup(500, 500)

# 循环绘制七段数码管
while True:
    turtle.clear()
    draw_time()
    turtle.update()
    time.sleep(1)

    turtle.clear()
    draw_number()
    turtle.update()
    time.sleep(1)

turtle.done()

这段代码会在窗口中交替绘制当前时间和自己的学号的七段数码管，每隔一秒钟切换一次。