Question

我需要指出正在解决这个问题的正确方向：

假设我正在读取C程序的输出，如下所示：

while True:
    ln = p.stdout.readline()
    if '' == ln:
        break
    #do stuff here with ln

我的输出看起来就像这行一样：

TrnIq: Thread on CPU 37
TrnIq: Thread on CPU 37 but will be moved to CPU 44
IP-Thread on CPU 33
FANOUT Thread on CPU 37
Filter-Thread on CPU 38 but will be moved to CPU 51
TRN TMR Test 2 Supervisor Thread on CPU 34
HomographyWarp Traking Thread[0] on CPU 26

我想将“TrnIq：Thread on”和“37”捕获为2个单独的变量：字符串和输出中的数字“TrnIq：CPU 37上的线程”。

对于其他行来说，它非常相同，例如捕获“HomographyWarp Traking Thread [0] on”和“C 26上的HomographyWarp Traking Thread [0]”中的＃“26”。

唯一真正的挑战是这样的行：“CPU 38上的过滤器线程，但将被移动到CPU 51”这行我需要“Filer-Thread”而＃“51”不是第一个＃“38 ”

Python有很多不同的方法可以做到这一点我甚至不知道从哪里开始！

提前致谢！

Answer 1

以下内容应该返回一个信息元组，假设ln是您的数据的一行（编辑为包括将CPU值转换为int）：

match = re.match(r'(.*?)(?: on CPU.*)?(?: (?:on|to) CPU )(.*)', ln).groups()
if match:
    proc, cpu = match.groups()
    cpu = int(cpu)

示例：

>>> import re
>>> for ln in lines:
...     print re.match(r'(.*?)(?: on CPU.*)?(?: (?:on|to) CPU )(.*)', ln).groups()
... 
('TrnIq: Thread', '37')
('TrnIq: Thread', '44')
('IP-Thread', '33')
('FANOUT Thread', '37')
('Filter-Thread', '51')
('TRN TMR Test 2 Supervisor Thread', '34')
('HomographyWarp Traking Thread[0]', '26')

说明：

(.*?)          # capture zero or more characters at the start of the string,
               #   as few characters as possible
(?: on CPU.*)? # optionally match ' on CPU' followed by any number of characters,
               #   do not capture this
(?: (?:on|to) CPU )  # match ' on CPU ' or ' to CPU ', but don't capture
(.*)           # capture the rest of the line

Rubular：http://www.rubular.com/r/HqS9nGdmbM

Answer 2

在这里，正则表达式对我来说似乎有些过分。 [免责声明：我不喜欢正则表达式，但是喜欢Python，所以尽可能用Python编写，不要编写正则表达式。由于我从未完全理解的原因，这被认为是令人惊讶的。]

s = """TrnIq: Thread on CPU 37
TrnIq: Thread on CPU 37 but will be moved to CPU 44
IP-Thread on CPU 33
FANOUT Thread on CPU 37
Filter-Thread on CPU 38 but will be moved to CPU 51
TRN TMR Test 2 Supervisor Thread on CPU 34
HomographyWarp Traking Thread[0] on CPU 26"""

for line in s.splitlines():
    words = line.split()
    if not ("CPU" in words and "on" in words): continue # skip uninteresting lines
    prefix_words = words[:words.index("on")+1]
    prefix = ' '.join(prefix_words)
    cpu = int(words[-1])
    print (prefix, cpu)

给出

('TrnIq: Thread on', 37)
('TrnIq: Thread on', 44)
('IP-Thread on', 33)
('FANOUT Thread on', 37)
('Filter-Thread on', 51)
('TRN TMR Test 2 Supervisor Thread on', 34)
('HomographyWarp Traking Thread[0] on', 26)

我认为我不需要将这些代码翻译成英文。

Answer 3

因此请使用正则表达式^(.*?)\s+on\s+CPU.*(?<=\sCPU)\s+(\d+)\s*$

import sys
import re

for ln in sys.stdin:
  m = re.match(r'^(.*?)\s+on\s+CPU.*(?<=\sCPU)\s+(\d+)\s*$', ln); 
  if m is not None:
    print m.groups();

查看并测试示例here。

Answer 4

在你提到的情况下，你总是想要第二个CPU号，所以可以用一个正则表达式完成：

# Test program
import re

lns = [
    "TrnIq: Thread on CPU 37",
    "TrnIq: Thread on CPU 37 but will be moved to CPU 44",
    "IP-Thread on CPU 33",
    "FANOUT Thread on CPU 37",
    "Filter-Thread on CPU 38 but will be moved to CPU 51",
    "TRN TMR Test 2 Supervisor Thread on CPU 34",
    "HomographyWarp Traking Thread[0] on CPU 26"
]

for ln in lns:
    test    = re.search("(?P<process>.*Thread\S* on).* CPU (?P<cpu>\d+)$", ln)
    print "%s: '%s' on CPU #%s" % ( ln, test.group('process'), test.group('cpu'))

在一般情况下，您可能希望区分案例（例如，CPU上的线程，移动的线程，子线程......）。为此，您可以一个接一个地使用几个re.search（）。例如：

# This search recognizes lines of the form "...Thread on CPU so-and-so", and
# also lines that add "...but will be moved to CPU some-other-cpu".
test = re.search("(?P<process>.* Thread) on CPU (?P<cpu1>\d+)( but will be moved to CPU (?P<cpu2>\d+))*", ln)
if test:
   # Here we capture Process Thread, both moved and non moved
   if test.group('cpu2'):
       # We have process, cpu1 and cpu2: moved thread
   else:
       # Nonmoved task, we have test.group('process') and cpu1.
else:
   # No match, try some other regexp. For example processes with a thread number
   # between square brackets: "Thread[0]", which are not captured by the regex above.
   test = re.search("(?P<process>.*) Thread[(?P<thread>\d+)] on CPU (?P<cpu1>)", ln)
   if test:
       # Here we have Homography Traking in process, 0 in thread, 26 in cpu1

为获得最佳性能，最好先对频繁出现的线路进行测试。

Answer 5

通过两次正则表达式搜索可以非常简单地完成：

import re

while True:
    ln = p.stdout.readline()
    if '' == ln:
        break

    start_match = re.search(r'^(.*?) on', ln)
    end_match = re.search(r'(\d+)$', ln)
    process = start_match and start_match.group(0)
    process_number = end_match and end_match.group(0)

在Python中查找多个字符串出现的最佳方法

5 个答案: