Question

我的实验结果存储在.txt文件中。以下是output.txt

的示例

Initializing the time of all nodes on network 10.0.0.0 to: 0.0
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Run Experiment:

Start LTG Traffice  AP -> STA
START TIME:2015-10-28 09:17:55.460000

Stop  LTG - AP -> STA
 ....Removing LTG+Saving and Writing Logs file after 0.3 s
END TIME:2015-10-28 09:18:25.467000

Log Sizes:  AP  = 14,155,896 bytes
            STA = 26,162,648 bytes

Initializing the time of all nodes on network 10.0.0.0 to: 0.0
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Run Experiment:

Start LTG Traffice  AP -> STA
START TIME:2015-10-28 09:20:32.499000

Stop  LTG - AP -> STA
 ....Removing LTG+Saving and Writing Logs file after 0.3 s
END TIME:2015-10-28 09:21:02.505000

Log Sizes:  AP  = 14,152,304 bytes
            STA = 26,163,856 bytes
Initializing the time of all nodes on network 10.0.0.0 to: 0.0
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Run Experiment:

Start LTG Traffice  AP -> STA
START TIME:2015-10-28 09:23:09.512000

Stop  LTG - AP -> STA
 ....Removing LTG+Saving and Writing Logs file after 0.3 s
END TIME:2015-10-28 09:23:39.518000

Log Sizes:  AP  = 12,144,180 bytes
            STA = 22,720,608 bytes

在每次实验之后，在output.txt中输出以下python脚本输出，其中始终包含以下信息：

Initializing the time of all nodes on network 10.0.0.0 to: 0.0
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Run Experiment:

Start LTG Traffice  AP -> STA
START TIME:2015-10-28 09:23:09.512000

Stop  LTG - AP -> STA
 ....Removing LTG+Saving and Writing Logs file after 0.3 s
END TIME:2015-10-28 09:23:39.518000

Log Sizes:  AP  = 12,144,180 bytes
            STA = 22,720,608 bytes

如何提取START TIME信息并存储在new.txt中，如：

2015-10-28 09:17:55.460000
2015-10-28 09:20:32.499000
2015-10-28 09:23:09.512000

Answer 1

我的尝试如下 - 基于正则表达式。

import re

f = open(r"C:\log.txt",'rb')

pattern = re.findall(r'(?<=START TIME:)([0-9-:\s.]+)$',f.read(),re.M|re.I)
for i in pattern:
    print i.strip()

打印

2015-10-28 09:17:55.460000
2015-10-28 09:20:32.499000
2015-10-28 09:23:09.512000

正则表达式的说明

（？＆lt; = START TIME :)（[0-9 - ：\ s。] +）$

(?<=START TIME:)([0-9-:\s.]+)$

选项：不区分大小写;确切间距;点不匹配换行符; ^ $匹配换行符处;只有正则表达式语法

断言下面的正则表达式可以匹配，匹配结束于此位置（正向后看）(?<=START TIME:)
- 字面匹配字符串“START TIME：”（不区分大小写）START TIME:
匹配下面的正则表达式并将其匹配捕获到反向引用号1 ([0-9-:\s.]+)
- 匹配以下列表中的单个字符[0-9-:\s.]+
  - 在一次和无限次之间，尽可能多次，根据需要回馈（贪婪）+
  - “0”和“9”0-9
  - 列表中的单个字符“ - ：”-:
  - “空格字符”（任何Unicode分隔符，制表符，换行符，回车符，垂直制表符，换页符，下一行）\s
  - 字面字符“。”.
在行尾（位于字符串末尾或换行符之前）断言位置（换行符）$

修改

在

之下获得两次小数点击

import re

f = open(r"C:\Users\Winrock\Desktop\log.txt",'rb')

pattern = re.findall(r'(?<=START TIME:)([0-9-:\s.]+)$',f.read(),re.M|re.I)
for i in pattern:
    data = i.strip()
    print data [0:len(data)-4]

Answer 2

此代码可以为您提供结果：

fout = open('new.txt', 'w')
for line in open('output.txt', 'r'):
    if line.startswith('START TIME'):
        fout.write("%s\n" % line.split('START TIME:')[1].strip())

Answer 3

我喜欢@SIslam的答案。

以下是使用str.partition的替代实现：

<强> extractstarttime.py：

with open('experiment.log', 'rU') as efile:
    with open('starttimes.log', 'a') as sfile:
        for line in efile:
            if line.startswith('START TIME:'):
                starttime = line.partition(':')[2].strip()
                sfile.write(starttime+'\n')

<强>输出：

$ python extractstarttime.py
$ cat starttimes.log
2015-10-28 09:17:55.460000
2015-10-28 09:20:32.499000
2015-10-28 09:23:09.512000

如何从.txt文件中提取某些关键字后出现的某些数据

3 个答案:

正则表达式的说明

（？＆lt; = START TIME :)（[0-9 - ：\ s。] +）$