标签：读写文件 star love 代码块 index fuse yesterday foo shift
文件操作
文本文件可存储的数据量多得难以置信：天气数据、交通数据、社会经济数据、文学作品等. 每当需要分析后修改存储在文件中的信息时，读取文件都很有用,对数据分析应用程序来说尤其如此. 学习文件的处理，可以让程序能够快速地分析大量的数据.
1. 对文件的操作流程：
首先打开文件，得到文件句柄并赋值给一个变量， 然后通过句柄对文件进行操作，操作完毕后，最后关闭文件.
现有文件如下
Somehow, it seems the love I knew was always the most destructive kind
不知为何，我经历的爱情总是最具毁灭性的的那种Yesterday when I was young昨日当我年少轻狂The taste of life was sweet生命的滋味是甜的As rain upon my tongue就如舌尖上的雨露I teased at life as if it were a foolish game我戏弄生命 视其为愚蠢的游戏The way the evening breeze就如夜晚的微风May tease the candle flame逗弄蜡烛的火苗The thousand dreams I dreamed我曾千万次梦见The splendid things I planned那些我计划的绚丽蓝图I always built to last on weak and shifting sand但我总是将之建筑在易逝的流沙上I lived by night and shunned the naked light of day我夜夜笙歌 逃避白昼赤裸的阳光And only now I see how the time ran away事到如今我才看清岁月是如何匆匆流逝Yesterday when I was young昨日当我年少轻狂So many lovely songs were waiting to be sung有那么多甜美的曲儿等我歌唱So many wild pleasures lay in store for me有那么多肆意的快乐等我享受And so much pain my eyes refused to see还有那么多痛苦 我的双眼却视而不见I ran so fast that time and youth at last ran out我飞快地奔走 最终时光与青春消逝殆尽I never stopped to think what life was all about我从未停下脚步去思考生命的意义And every conversation that I can now recall如今回想起的所有对话Concerned itself with me and nothing else at all除了和我相关的 什么都记不得了The game of love I played with arrogance and pride我用自负和傲慢玩着爱情的游戏And every flame I lit too quickly, quickly died所有我点燃的火焰都熄灭得太快The friends I made all somehow seemed to slip away所有我交的朋友似乎都不知不觉地离开了And only now I‘m left alone to end the play, yeah只剩我一个人在台上来结束这场闹剧Oh, yesterday when I was young噢 昨日当我年少轻狂So many, many songs were waiting to be sung有那么那么多甜美的曲儿等我歌唱So many wild pleasures lay in store for me有那么多肆意的快乐等我享受And so much pain my eyes refused to see还有那么多痛苦 我的双眼却视而不见There are so many songs in me that won‘t be sung我有太多歌曲永远不会被唱起I feel the bitter taste of tears upon my tongue我尝到了舌尖泪水的苦涩滋味The time has come for me to pay for yesterday终于到了付出代价的时间 为了昨日When I was young当我年少轻狂基本操作
f = open（‘lyrics‘） #打开文件
first_line = f.readline()
print("first line:", first_line) #读一行
print（‘我是分割线’.center(50,‘-‘)）
data = f.read() #读取剩下的内容，文件大的时候不要用
print（data）#打印文件
f.close() #关闭文件
打开文件的模式有如下方式：
"+" 表示可以同时读写某个文件
"U"表示在读取时，可以将 \r \n \r\n自动转换成 \n （与 r 或 r+ 模式同使用）
"b"表示处理二进制文件（如：FTP发送上传ISO镜像文件，linux可忽略，windows处理二进制文件时需标注）
其他语法：
def close(self): # real signature unknown; restored from __doc__
"""
Close the file.
A closed file cannot be used for further I/O operations. close() may be
called more than once without error.
"""
pass
def fileno(self, *args, **kwargs): # real signature unknown
""" Return the underlying file descriptor (an integer). """
pass
def isatty(self, *args, **kwargs): # real signature unknown
""" True if the file is connected to a TTY device. """
pass
def read(self, size=-1): # known case of _io.FileIO.read
"""
注意，不一定能全读回来
Read at most size bytes, returned as bytes.
Only makes one system call, so less data may be returned than requested.
In non-blocking mode, returns None if no data is available.
Return an empty bytes object at EOF.
"""
return ""
def readable(self, *args, **kwargs): # real signature unknown
""" True if file was opened in a read mode. """
pass
def readall(self, *args, **kwargs): # real signature unknown
"""
Read all data from the file, returned as bytes.
In non-blocking mode, returns as much as is immediately available,
or None if no data is available. Return an empty bytes object at EOF.
"""
pass
def readinto(self): # real signature unknown; restored from __doc__
""" Same as RawIOBase.readinto(). """
pass #不要用,没人知道它是干嘛用的
def seek(self, *args, **kwargs): # real signature unknown
"""
Move to new file position and return the file position.
Argument offset is a byte count. Optional argument whence defaults to
SEEK_SET or 0 (offset from start of file, offset should be >= 0); other values
are SEEK_CUR or 1 (move relative to current position, positive or negative),
and SEEK_END or 2 (move relative to end of file, usually negative, although
many platforms allow seeking beyond the end of a file).
Note that not all file objects are seekable.
"""
pass
def seekable(self, *args, **kwargs): # real signature unknown
""" True if file supports random-access. """
pass
def tell(self, *args, **kwargs): # real signature unknown
"""
Current file position.
Can raise OSError for non seekable files.
"""
pass
def truncate(self, *args, **kwargs): # real signature unknown
"""
Truncate the file to at most size bytes and return the truncated size.
Size defaults to the current file position, as returned by tell().
The current file position is changed to the value of size.
"""
pass
def writable(self, *args, **kwargs): # real signature unknown
""" True if file was opened in a write mode. """
pass
def write(self, *args, **kwargs): # real signature unknown
"""
Write bytes b to file, return number written.
Only makes one system call, so not all of the data may be written.
The number of bytes actually written is returned. In non-blocking mode,
returns None if the write would block.
"""
pass
with语句
为了避免打开文件后忘记关闭，可以通过管理上下文，即：
with open（‘log’,‘r‘） as f:
如此方式，当with代码块执行完毕时，内部会自动关闭并释放文件资源。
标签：读写文件 star love 代码块 index fuse yesterday foo shift
原文地址：https://www.cnblogs.com/Chiu2018/p/9254431.html
