python读取文件的前几行

文件内容rolling.txt:

There's a fire starting in my heart
我怒火中烧
Reaching a fever pitch and it's bringing me out the dark
熊熊烈焰带我走出黑暗
Finally, I can see you crystal clear
最终 我将你看得一清二楚
Go ahead and sell me out and I'll lay your ship bare
去吧 出卖我 我会让你一无全部
See how I'll leave with every piece of you
看我怎么离你而去 带走你的一切
Don't underestimate the things that I will do
不要低估我将来的所作所为
There's a fire starting in my heart
我怒火中烧
Reaching a fever pitch and it's bring me out the dark
熊熊烈焰带我走出黑暗
The scars of your love remind me of us
你的爱情伤痕让我想起了我们曾经的甜蜜
They keep me thinking that we almost had it all
它们总在提醒我 我们几乎拥有了一切
The scars of your love, they leave me breathless
你的爱情伤痕 让我窒息
I can't help feeling
我不禁心生感触
We could have had it all
我们本该拥有一切
(You're gonna wish you never had met me)
(你会祈祷 要是从未遇见我该有多好)
Rolling in the deep
内心深处爱恨交织
(Tears are gonna fall, rolling in the deep)
(眼泪快要掉下来，内心深处爱恨交织)
You had my heart inside your hand
你俘虏了我的芳心
(You're gonna wish you never had met me)
(你会祈祷 要是从未遇见我该有多好)
And you played it to the beat
但是你玩弄它 伴着每一次心跳
(Tears are gonna fall, rolling in the deep)
(眼泪快要掉下来，内心深处爱恨交织)
Baby, I have no story to be told
宝贝 我没有故事可讲
But I've heard one on you and I'm gonna make your head burn
但是我听说了一件有关你的事情 我会让你焦头烂额
Think of me in the depths of your despair
在绝望的深渊中想起我
Making a home down there as mine sure won't be shared
就在那里安家吧 因为我的家园绝对没你的份
The scars of your love remind me of us
你的爱情伤痕让我想起了我们曾经的甜蜜
(You're gonna wish you never had met me)
(你会祈祷 要是从未遇见我该有多好)
They keep me thinking that we almost had it all
它们总在提醒我 我们几乎拥有了一切

一行行的读取文件前5行

第一种方法：

 for i in range(5):
     print(f.readline().strip())

第二种方法：

line_nu = 0#计数器
for line in f:#一行行的把数据从硬盘加载到内存里读出来
    if line_nu<5:#读取前五行
        print(line.strip())
        line_nu += 1
    else:
        break

最简单的两种方法。