读取文件中的内容：
with open('data.txt','r') as f:
data_list = f.readlines()#每一行是一个字符串
data_list = [i.strip('\n') for i in data_list]#去掉换行符
data_list = [i.split(',') for i in data_list]#每一行以逗号分隔字符
data = [(float(i[0]),float(i[1]),float(i[2])) for i in data_list]#将每一个字符变成float型
