如何在 Python 中编写带有命名组的正则表达式来匹配这个？

Question

我有一个包含以下行的文件。

comm=adbd pid=11108 优先级=120 成功=1 target_cpu=001

我写了下面的正则表达式来匹配。

_sched_wakeup_pattern = re.compile(r"""
comm=(?P<next_comm>.+?)
\spid=(?P<next_pid>\d+)
\sprio=(?P<next_prio>\d+)
\ssuccess=(?P<success>\d)
\starget_cpu=(?P<target_cpu>\d+)
""", re.VERBOSE)

但是现在我也有像下面这样的行，其中不存在成功组件。

comm=rcu_preempt pid=7 prio=120 target_cpu=007

如何在此处修改我的正则表达式以匹配这两种情况？我尝试在包含 "success" 的行中的任何地方放置一个 *，但它会抛出错误。

Answer 1

匹配 0 或 1 重复 (your_string)?。

_sched_wakeup_pattern = re.compile(r"""
comm=(?P<next_comm>.+?)
\spid=(?P<next_pid>\d+)
\sprio=(?P<next_prio>\d+)
\s?(success=(?P<success>\d))?
\starget_cpu=(?P<target_cpu>\d+)
""", re.VERBOSE)

给你在这里它寻找整个字符串，所以它也打印 success=:

output =>
('rcu_preempt', '7', '120', '', '', '007')
('kworker/u16:2', '73', '120', '', '', '006')
('kworker/u16:4', '364', '120', '', '', '005')
('adbd', '11108', '120', 'success=1', '1', '001')
('kworker/1:1', '16625', '120', 'success=1', '1', '001')
('rcu_preempt', '7', '120', 'success=1', '1', '002')

现在我们需要找到一种方法来删除 "success="。这似乎并不难。

[已编辑]
(?:\ssuccess=)?(?P<success>\d)? 效果很好。
通过 RomanPerekhrest

Answer 2

使用正则表达式非捕获组和regex.findall函数的解决方案：

import regex
...
fh = open('lines.txt', 'r');  // considering 'lines.txt' is your initial file
commlines = fh.read()

_sched_wakeup_pattern = regex.compile(r"""
comm=(?P<next_comm>[\S]+?)
\spid=(?P<next_pid>\d+)
\sprio=(?P<next_prio>\d+)
(?:\ssuccess=)?(?P<success>\d)?
\starget_cpu=(?P<target_cpu>\d+)
""", regex.VERBOSE)

result = regex.findall(_sched_wakeup_pattern, commlines)

template = "{0:15}|{1:10}|{2:9}|{3:7}|{4:10}" # column widths
print(template.format("next_comm", "next_pid", "next_prio", "success", "target_cpu")) # header

for t in result:
    print(template.format(*t))

美化输出：

next_comm      |next_pid  |next_prio|success|target_cpu
rcu_preempt    |7         |120      |       |007       
kworker/u16:2  |73        |120      |       |006       
kworker/u16:4  |364       |120      |       |005       
adbd           |11108     |120      |1      |001       
kworker/1:1    |16625     |120      |1      |001       
rcu_preempt    |7         |120      |1      |002

如何在 Python 中编写带有命名组的正则表达式来匹配这个？

How to write a regex in Python with named groups to match this?

python

regex

regex-group