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我遇到了一种情况,我想在正则表达式中使用非贪婪原子.*?
。非贪婪正则表达式基于正则表达式中的原子位置贪婪
set input "Device ID: HOST1
Interface: GigabitEthernet0/1, Port ID (outgoing port): GigabitEthernet2/43
Device ID: HOST2
Entry address(es):
Interface: GigabitEthernet0/2, Port ID (outgoing port): GigabitEthernet2/43
"
puts "======== Non-Greedy regex starting with some other patterns ========"
puts [ regexp -inline {Device\s+ID:.*?outgoing\s+port\):\s+} $input]
puts "======== Non-Greedy regex at first ========"
puts [ regexp -inline {.*?outgoing\s+port\):\s+} $input]
输出:
======== Non-Greedy regex starting with some other patterns ========
{Device ID: HOST1
Interface: GigabitEthernet0/1, Port ID (outgoing port): GigabitEthernet2/43
Device ID: HOST2
Entry address(es):
Interface: GigabitEthernet0/2, Port ID (outgoing port): }
======== Non-Greedy regex at first ========
{Device ID: HOST1
Interface: GigabitEthernet0/1, Port ID (outgoing port): }
.*?outgoing\s+port\):\s+
虽然是匹配直到第一次出现,所述图案Device\s+ID:.*?outgoing\s+port\):\s+
不是在比赛的第一个发生停止。
为什么非贪心匹配的行为会因为放置原子而受到影响?
呵呵,很好的回答,在回答时重新阅读它的记忆,但没有发现第一个操作符在'Device \ s + ...'中贪婪。所以如果我做得好,把第一个'\ s +'改成'\ s +?'应该做什么? – Tensibai
@Tensibai&@glenn:是的!使用'Device \ s +?ID:。*?outgoing \ s + port \':\ s +'它只匹配到第一个匹配项。这很棒。感谢格伦先生! – Dinesh