builtins.ValueError: could not convert string to float:的问题

import turtledef main():    turtle.title('数据驱动的动态绘制路径')    turtle.setup(800, 600, 0, 0)    pen = turtle.Turtle()    pen.width(5)    pen.shape("turtle")    pen.speed(5)    result = []    file = open("f://py_test.txt",'r')    for line in file:        print(line)        result.append(list(map(float, line.split(','))))    print(result)    for i in range(len(result)):        pen.color((result[i][3], result[i][4],result[i][5]))        pen.fd(result[i][0])        if result[i][1]:            pen.rt(result[i][2])        else:            pen.lt(result[i][2])if __name__ == '__main__':    main()

其中的result.append(list(map(float, line.split(','))))
出现问题，原因是在float（）转换字符串时，不能为空串或者‘\n’，否则就会报错