重新搜索python regexpr

Question

對於我的作業，我需要搜索一個程序並打印出每個用戶已打印多少頁。

date: 2012-11-25
printer on time:  0800 
23.96.82.161 user: pei printer: core 2 pages: 2 code: r n t h p r
28.104.177.80 user: isaac printer: poster pages: 4 code: p h
printer error:  out of paper  time: 1343
180.186.109.129 user: luis printer: core 2 pages: 2 code: k n h
194.96.54.184 user: isaac printer: sally pages: 6 code: p k r p f
122.230.32.236 user: luis printer: hill 3 pages: 8 code: n h n k q
printer off time: 2201

是程序將包含的示例，

for stringprint in logfile:
        userRegex = re.search('(\suser:\s)(.+?)(\sprinter:\s)', stringprint)
        if userRegex:
            userString = userRegex.group(2)
            numpages = int(re.search('(\spages:\s)(.+?)(\scode:\s)', stringprint).group(2))

            if userString not in users:
                user[userString] = numpages
            else:
                user[userString] += numpages

我的問題是re.search不能正常運行，我相信這種表達是正確的，但顯然不是。 我知道\\s匹配空格， .+?也匹配.+? 是與前面的令牌匹配的惰性版本。 一旦找到匹配項，我就使用user.Regex.group(2)將其設置為“用戶名”。 然后，我要從那里搜索頁面數和代碼（以確保正確匹配），然后繼續打印。 我知道此正則表達式無法正常工作，但我無法弄清楚自己在做什么錯。

當我通過模塊運行程序時，我得到：

Traceback (most recent call last): File "C:\\Users\\brandon\\Desktop\\project3\\project3\\pages.py", line 45, in <module> log2hist("log") # version 2. File "C:\\Users\\brandon\\Desktop\\project3\\project3\\pages.py", line 29, in log2hist numpages = int(re.search('(\\spages:\\s)(.+?)(\\scode:\\s)',stringprint).group(2)) AttributeError: 'NoneType' object has no attribute 'group'

Answer 1

描述

我建議切換您的Regex，這樣會更加靈活。 此正則表達式將執行以下操作：

• 捕獲用戶名
• 捕獲打印數量
• 允許用戶和頁面以任何順序顯示。 如果您想開始捕獲其他數據，這將很方便

正則表達式

^(?=.*?user:\s+(.*?)\s)(?=.*?pages:\s+(.*?)\s).*?$

解釋

NODE                     EXPLANATION
----------------------------------------------------------------------
  ^                        the beginning of a "line"
----------------------------------------------------------------------
  (?=                      look ahead to see if there is:
----------------------------------------------------------------------
    .*?                      any character except \n (0 or more times
                             (matching the least amount possible))
----------------------------------------------------------------------
    user:                    'user:'
----------------------------------------------------------------------
    \s+                      whitespace (\n, \r, \t, \f, and " ") (1
                             or more times (matching the most amount
                             possible))
----------------------------------------------------------------------
    (                        group and capture to \1:
----------------------------------------------------------------------
      .*?                      any character except \n (0 or more
                               times (matching the least amount
                               possible))
----------------------------------------------------------------------
    )                        end of \1
----------------------------------------------------------------------
    \s                       whitespace (\n, \r, \t, \f, and " ")
----------------------------------------------------------------------
  )                        end of look-ahead
----------------------------------------------------------------------
  (?=                      look ahead to see if there is:
----------------------------------------------------------------------
    .*?                      any character except \n (0 or more times
                             (matching the least amount possible))
----------------------------------------------------------------------
    pages:                   'pages:'
----------------------------------------------------------------------
    \s+                      whitespace (\n, \r, \t, \f, and " ") (1
                             or more times (matching the most amount
                             possible))
----------------------------------------------------------------------
    (                        group and capture to \2:
----------------------------------------------------------------------
      .*?                      any character except \n (0 or more
                               times (matching the least amount
                               possible))
----------------------------------------------------------------------
    )                        end of \2
----------------------------------------------------------------------
    \s                       whitespace (\n, \r, \t, \f, and " ")
----------------------------------------------------------------------
  )                        end of look-ahead
----------------------------------------------------------------------
  .*?                      any character except \n (0 or more times
                           (matching the least amount possible))
----------------------------------------------------------------------
  $                        before an optional \n, and the end of a
                           "line"

例子

正則表達式在線演示

http://fiddle.re/13chna

樣本Python代碼

https://repl.it/CJdF/0

import re

SampleString = '''date: 2012-11-25
printer on time:  0800 
23.96.82.161 user: pei printer: core 2 pages: 2 code: r n t h p r
28.104.177.80 user: isaac printer: poster pages: 4 code: p h
printer error:  out of paper  time: 1343
180.186.109.129 user: luis printer: core 2 pages: 2 code: k n h
194.96.54.184 user: isaac printer: sally pages: 6 code: p k r p f
122.230.32.236 user: luis printer: hill 3 pages: 8 code: n h n k q
printer off time: 2201'''
print (SampleString)

## Here re.findall()
Regex=re.compile(r'^(?=.*?user:\s+(.*?)\s)(?=.*?pages:\s+(.*?)\s).*?$',re.MULTILINE)
Matches = Regex.findall( SampleString) 
Count = 0
for Match in Matches:
    # do something with each found email string
    print("[" + str(Count) + "][0] = " + Match[0])
    print("[" + str(Count) + "][1] = " + Match[1])
    print("")
    Count = Count + 1

樣本輸出

[0][0] = pei
[0][1] = 2

[1][0] = isaac
[1][1] = 4

[2][0] = luis
[2][1] = 2

[3][0] = isaac
[3][1] = 6

[4][0] = luis
[4][1] = 8