Question

我一直在尝试解析多行字符串并从中提取子字符串。我跑＆＃34; ifconfig＆＃34;从ruby文件命令并尝试查找第一个网络接口名称的名称。＆＃34; ifconfig＆＃34;的结果命令就像这样

eth0      Link encap:Ethernet  HWaddr *****  
      UP BROADCAST MULTICAST  MTU:1500  Metric:1
      RX packets:0 errors:0 dropped:0 overruns:0 frame:0
      TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
      collisions:0 txqueuelen:1000 
      RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

lo        Link encap:Local Loopback  
      inet addr:127.0.0.1  Mask:255.0.0.0
      UP LOOPBACK RUNNING  MTU:65536  Metric:1
      RX packets:5439 errors:0 dropped:0 overruns:0 frame:0
      TX packets:5439 errors:0 dropped:0 overruns:0 carrier:0
      collisions:0 txqueuelen:0 
      RX bytes:480911 (469.6 KiB)  TX bytes:480911 (469.6 KiB)

wlan1     Link encap:Ethernet  HWaddr ***** 
      UP BROADCAST MULTICAST  MTU:1500  Metric:1
      RX packets:0 errors:0 dropped:0 overruns:0 frame:0
      TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
      collisions:0 txqueuelen:1000 
      RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

wlan5     Link encap:Ethernet  HWaddr ***** 
      inet addr:*****  Bcast:*****  Mask:******
      UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
      RX packets:30423 errors:0 dropped:5903 overruns:0 frame:0
      TX packets:14879 errors:0 dropped:1 overruns:0 carrier:0
      collisions:0 txqueuelen:1000 
      RX bytes:4968104 (4.7 MiB)  TX bytes:1465216 (1.3 MiB)

我希望摘录第一个＆＃34; wlan＆＃34;从这个字符串是wlan1。顺序总是相同但是第一个wlan可能是＆＃34; wlan0＆＃34;，＆＃34; wlan1＆＃34;等......我可以这样得到它然而我想知道有没有更好的方法呢？

parsing_string = `ifconfig`

position= parsing_string.index('wlan')
puts parsing_string[position..position+4]

Answer 1

如果没有wlanX界面怎么办？由于:index可以返回nil，您最终会得到NoMethodError

我宁愿尝试类似：puts parsing_string[/(wlan\d)/, 1]

在字符串中查找特定的子字符串

1 个答案: