Python grep and cut

Question

在Linux中，通过使用grep，cut或awk之类的工具很容易获得某些字符串。

此show version样本取自https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst9300/software/release/16-6/configuration_guide/sys_mgmt/b_166_sys_mgmt_9300_cg/b_166_sys_mgmt_9300_cg_chapter_01.html

wolf@linux:~$ cat shver
cisco C9300-48P (X86) processor with 818597K/6147K bytes of memory.
Processor board ID FCW2049G03S
2048K bytes of non-volatile configuration memory.
8388608K bytes of physical memory.
1638400K bytes of Crash Files at crashinfo:.
11264000K bytes of Flash at flash:.
0K bytes of WebUI ODM Files at webui:.
Model Number                       : C9300-48P

Base Ethernet MAC Address          : 04:6c:9d:01:3b:80
Motherboard Assembly Number        : 73-17956-04
Motherboard Serial Number          : FOC20465ABU
Model Revision Number              : P4B
Motherboard Revision Number        : 04
Model Number                       : C9300-48P
System Serial Number               : FCW2049G03S

wolf@linux:~$ 

删除并剪切

wolf@linux:~$ grep 'Model Number' shver | cut -d : -f 2
 C9300-48P
 C9300-48P
wolf@linux:~$ 

删除多余的空间（如果有更好的解决方案，请告诉我）

wolf@linux:~$ grep 'Model Number' shver | cut -d : -f 2 | cut -d ' ' -f 2
C9300-48P
C9300-48P
wolf@linux:~$ 

选择第一个输出

wolf@linux:~$ grep 'Model Number' shver | cut -d : -f 2 | cut -d ' ' -f 2 | head -1
C9300-48P
wolf@linux:~$ 

那是在Linux中。我打算用Python编写类似的代码。

我的尝试目前仍然没有用。

定义颤抖字符串

>>> shver = '''cisco C9300-48P (X86) processor with 818597K/6147K bytes of memory.
... Processor board ID FCW2049G03S
... 2048K bytes of non-volatile configuration memory.
... 8388608K bytes of physical memory.
... 1638400K bytes of Crash Files at crashinfo:.
... 11264000K bytes of Flash at flash:.
... 0K bytes of WebUI ODM Files at webui:.
... Model Number                       : C9300-48P
... 
... Base Ethernet MAC Address          : 04:6c:9d:01:3b:80
... Motherboard Assembly Number        : 73-17956-04
... Motherboard Serial Number          : FOC20465ABU
... Model Revision Number              : P4B
... Motherboard Revision Number        : 04
... Model Number                       : C9300-48P
... System Serial Number               : FCW2049G03S
... '''
>>> 

验证

>>> shver
'cisco C9300-48P (X86) processor with 818597K/6147K bytes of memory.\nProcessor board ID FCW2049G03S\n2048K bytes of non-volatile configuration memory.\n8388608K bytes of physical memory.\n1638400K bytes of Crash Files at crashinfo:.\n11264000K bytes of Flash at flash:.\n0K bytes of WebUI ODM Files at webui:.\nModel Number                       : C9300-48P\n\nBase Ethernet MAC Address          : 04:6c:9d:01:3b:80\nMotherboard Assembly Number        : 73-17956-04\nMotherboard Serial Number          : FOC20465ABU\nModel Revision Number              : P4B\nMotherboard Revision Number        : 04\nModel Number                       : C9300-48P\nSystem Serial Number               : FCW2049G03S\n'
>>> 

创建列表

>>> shver_list = shver.splitlines()
>>> shver_list
['cisco C9300-48P (X86) processor with 818597K/6147K bytes of memory.', 'Processor board ID FCW2049G03S', '2048K bytes of non-volatile configuration memory.', '8388608K bytes of physical memory.', '1638400K bytes of Crash Files at crashinfo:.', '11264000K bytes of Flash at flash:.', '0K bytes of WebUI ODM Files at webui:.', 'Model Number                       : C9300-48P', '', 'Base Ethernet MAC Address          : 04:6c:9d:01:3b:80', 'Motherboard Assembly Number        : 73-17956-04', 'Motherboard Serial Number          : FOC20465ABU', 'Model Revision Number              : P4B', 'Motherboard Revision Number        : 04', 'Model Number                       : C9300-48P', 'System Serial Number               : FCW2049G03S']
>>> 

下一步是查找是否存在字符串“型号”并打印出该行

>>> if 'Model Number' in shver_list:
...     'yes'
... else:
...     'no'
... 
'no'
>>> 

我如何打印出包含“型号”的行？

>>> for i in shver_list:
...     if 'Model Number' in shver_list:
...             i
... 
>>> 

期望的输出

C9300-48P

Answer 1

您可以将数据解析为字典，这使得访问相关信息变得非常容易：

shver = '''cisco C9300-48P (X86) processor with 818597K/6147K bytes of memory.
Processor board ID FCW2049G03S
2048K bytes of non-volatile configuration memory.
8388608K bytes of physical memory.
1638400K bytes of Crash Files at crashinfo:.
11264000K bytes of Flash at flash:.
0K bytes of WebUI ODM Files at webui:.
Model Number                       : C9300-48P

Base Ethernet MAC Address          : 04:6c:9d:01:3b:80
Motherboard Assembly Number        : 73-17956-04
Motherboard Serial Number          : FOC20465ABU
Model Revision Number              : P4B
Motherboard Revision Number        : 04
Model Number                       : C9300-48P
System Serial Number               : FCW2049G03S
'''

attributes = {}

for line in shver.splitlines():
    if ':' in line:  # we just take lines that contain a colon
        item, value = line.strip().split(':', 1)  # Split at the first colon!
        attributes[item.strip()] = value.strip()  # remove all whitespaces

print(attributes['Model Number'])
print(attributes['System Serial Number'])

输出：

C9300-48P
FCW2049G03S

Answer 2

您必须过滤列表中的条目。如果直接过滤，您正在寻找的是字面上是“型号”的行。

这将打印包含子字符串“型号”的所有行。

modelnumbers = [line for line in shver_list if 'Model Number' in line]
print(modelnumbers)`

要获得所需的输出，请使用第一个结果，并去除不需要的所有内容。

print(modelnumbers[0].split(":")[1].strip())

Answer 3

从shver_list步骤开始，您可以这样做：

for item in shver_list:
    if "Model Number" in item:
        break

因此，一旦找到匹配项，它将打破循环并查看item中的内容：

>>> item
'Model Number                       : C9300-48P'

现在我们可以在:上分割它（注意周围的空格并得到：

>>> items.split(" : ")
['Model Number                      ', 'C9300-48P']

因此所需元素位于此列表的第一个位置。

总计：

for item in shver_list:
    if "Model Number" in item:
        break
desired = item.split(" : ")[1]

另一种处理方法是使用正则表达式。这次我们从shver字符串中获取它：

import re
matches_gen = re.finditer(r"Model Number\s+:\s*(.+)", shver)
desired = next(matches_gen).group(1)

我们使用finditer进行延迟评估，并且因为我们想要第一次出现，所以我们在其上使用一个next并采用匹配组来获得所需的C9300-48P结果。