读取数据：
file=open("c:\\temp\\u.data")

print(file.readline())



读取全部
file=open("c:\\temp\\u.data")
list = file.readlines()
for i in range(0,len(list)):
    print(list[i])



file=open("c:\\temp\\new.txt","w")
file.write("你好！")
file.close()

with open("c:\\temp\\new1.txt","w") as file:
    file.write("你好！")


在文件前增加标题头
with open("c:\\temp\\u.data","r") as file:
    list=file.readlines()
for i in range(0,len(list)):
    list[i]=str(i+1)+' '+list[i]
with open("c:\\temp\\u1.data","w") as file:
    file.writelines(list)