Python读取文件的最后一行（非空行）

py3study

发布于 2020-01-07 14:56:33

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发布于 2020-01-07 14:56:33

文章被收录于专栏：python3python3

利用Python读取文件（针对大文件和小文件两种）的首行（第一行）和末行（最后一行）。脚本借鉴了前人的两种处理思路（在下面的脚本中有注释说明引用出处），并修正了原先两种处理方法中如果文件末尾含有多个空行而返回空行的问题。

脚本内容可以从GitHub上获取：

https://github.com/DingGuodong/LinuxBashShellScriptForOps/blob/master/functions/file/getFileLastLine.py

脚本内容如下：

#!/usr/bin/python
#?encoding:?utf-8
#?-*-?coding:?utf8?-*-
"""
Created?by?PyCharm.
File:???????????????LinuxBashShellScriptForOps:getFileLastLine.py
User:???????????????Guodong
Create?Date:????????2016/9/1
Create?Time:????????11:05
?"""
import?os


#?Refer:?http://www.pythonclub.org/python-files/last-line
def?get_last_line(inputfile):
????filesize?=?os.path.getsize(inputfile)
????blocksize?=?1024
????dat_file?=?open(inputfile,?'rb')
????last_line?=?""
????if?filesize?>?blocksize:
????????maxseekpoint?=?(filesize?//?blocksize)
????????dat_file.seek((maxseekpoint?-?1)?*?blocksize)
????elif?filesize:
????????#?maxseekpoint?=?blocksize?%?filesize
????????dat_file.seek(0,?0)
????lines?=?dat_file.readlines()
????if?lines:
????????last_line?=?lines[-1].strip()
????#?print?"last?line?:?",?last_line
????dat_file.close()
????return?last_line


#?Refer:?http://code.activestate.com/recipes/578095/
def?print_first_last_line(inputfile):
????filesize?=?os.path.getsize(inputfile)
????blocksize?=?1024
????dat_file?=?open(inputfile,?'rb')
????headers?=?dat_file.readline().strip()
????if?filesize?>?blocksize:
????????maxseekpoint?=?(filesize?//?blocksize)
????????dat_file.seek(maxseekpoint?*?blocksize)
????elif?filesize:
????????maxseekpoint?=?blocksize?%?filesize
????????dat_file.seek(maxseekpoint)
????lines?=?dat_file.readlines()
????if?lines:
????????last_line?=?lines[-1].strip()
????#?print?"first?line?:?",?headers
????#?print?"last?line?:?",?last_line
????return?headers,?last_line


#?My?Implementation
def?get_file_last_line(inputfile):
????filesize?=?os.path.getsize(inputfile)
????blocksize?=?1024
????with?open(inputfile,?'rb')?as?f:
????????last_line?=?""
????????if?filesize?>?blocksize:
????????????maxseekpoint?=?(filesize?//?blocksize)
????????????f.seek((maxseekpoint?-?1)?*?blocksize)
????????elif?filesize:
????????????f.seek(0,?0)
????????lines?=?f.readlines()
????????if?lines:
????????????lineno?=?1
????????????while?last_line?==?"":
????????????????last_line?=?lines[-lineno].strip()
????????????????lineno?+=?1
????????return?last_line

#?Test?purpose
#?print?get_last_line(os.path.abspath(__file__))
#?print?print_first_last_line(os.path.abspath(__file__))
#?print?get_file_last_line(os.path.abspath(__file__))

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原始发表：2019-09-10 ，如有侵权请联系 cloudcommunity@tencent.com 删除

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