我想在python中使用正则表达式匹配换行符后面的字符串。

Question

Device ID: xyz
Entry address(es): 
 IP address: 10.3.10.46
Platform: WS-x,  Capabilities: Switch IGMP 
Interface: GigabitEthernet9/33,  Port ID (outgoing port): GigabitEthernet0/2
Holdtime : 177 sec
Management address(es): 
 IP address: 10.3.10.46

上面是上面file.From中的一个片段，我想通过只匹配下面两行来收集ip地址。输入地址: IP地址: 10.3.10.46或管理地址: IP地址: 10.3.10.46

我编写的正则表达式如下所示，它不起作用，我无法解决如何在正则表达式中显示"address(es):“之后的新行。

f = open(fileName)
for line in f:
    matchObj1 = re.match(r'Entry address\(es\):\s+IP address: ([0-9.]+)', line)
    if matchObj1:
    print "IP Address = ", matchObj1.group(1)

    matchObj2 = re.match(r'Entry address\(es\):\s+IP address: ([0-9.]+)', line)
    if matchObj2:
    print "IP Address = ", matchObj2.group(1)

请帮帮忙。谢谢。

Answer 1

您不需要为此使用正则表达式。您的输入看起来像配置文件或程序的输出，并且易于解析。

def get_addresses(fname):
    addresses = {}
    with open(fname) as f:
        lines = [l.strip().lower() for l in f]

    for i, line in enumerate(lines):
        if line.startswith("ip address"):
            ip = line.split(": ")[1]
            address_type = lines[i-1]
            if address_type == "entry address(es):":
                addresses["entry"] = ip
            elif address_type == "management address(es):":
                addresses["management"] = ip
            # Add additional address type handling here

    return addresses

Answer 2

您需要使用re.search而不是re.match，从字符串的一开始就使用re.match进行匹配：

>>> s = 'Device ID: xyz\nEntry address(es): \n      IP address: 10.3.10.46\n    Platform: WS-x,  Capabilities: Switch IGMP \n    Interface: GigabitEthernet9/33,  Port ID (outgoing port): GigabitEthernet0/2\n    Holdtime : 177 sec'
>>> re.search(r'Entry address\(es\):\s+IP address: ([0-9.]+)', s).group(1)
'10.3.10.46'

match()

re.match()只在字符串的开头检查匹配，而re.search()只检查字符串中任何位置的匹配。