Null value and whitespace in Regex-CodePudding

I have the following Regex:

^(?P<port_name>[\w\d\/] )[^\S\r\n] (?P<description>[\S]  ?[\S] )\s (?P<duplex>[\w] )\s

That I use on the following data:

>show interfaces status
Port      Description     Duplex Speed   Neg  Link   Flow  M  VLAN
                                              State  Ctrl
--------- --------------- ------ ------- ---- ------ ----- -- -------------------
Te1/0/1   CVH10 Mgt Clstr Full   10000   Off  Up     On    T  (1),161-163
Te1/0/2   CVH10 VM 1      Full   10000   Off  Up     On    T  (1),11,101,110,
                                                              120,130,140,150,
                                                              160,170,180,190,
                                                              200,210,230,240,
                                                              250,666,999
Fo2/1/1                   N/A    N/A     N/A  Detach N/A
Te2/0/8                   Full   10000   Off  Down   Off   A  1

Which gives me this result (

I can't seem to figure out:

How to match the description without also matching the duplex value of Full, because of it's spaces.
How to match a value of null when there is no discription avalible as seen in the last two lines.

I'm starting to learn Regex and hope someone can help me out.

CodePudding user response：

You can not assume that the columns are divided by at least 2 whitespace chars, so in that case you can make the pattern a bit more specific.

Note that \w also matches \d.

^(?P<port_name>[\w\/] )[^\S\r\n] (?P<description>(?!Full\b|N\/A\b)\S (?:[^\S\r\n] \S )*?[^\S\r\n] )?(?P<duplex>Full|N\/A)[^\S\r\n] (?P<speed>\d |N\/A)\b

^ Start of string
(?P<port_name>[\w\/] )[^\S\r\n] port_name match 1 word chars or -
(?P<description> description
- (?!Full\b|N\/A\b) Negative lookahead, assert not Full or N/A directly to the right
- \S (?:[^\S\r\n] \S )*? Match 1 non whitespace chars and optionally repeat 1 spaces and 1 non whitespace chars, as least as possible
- [^\S\r\n] Match 1 spaces (whitespace chars without a newline)
)? Close the group and make it optional
(?P<duplex>Full|N\/A)[^\S\r\n] duplex Match either Full or N/A
(?P<speed>\d |N\/A)\b speed Match either 1 digits or N/A

See a regex 101 demo.

To match all values including optional fields:

^(?P<port_name>[\w\/] )[^\S\r\n] (?P<description>(?!Full\b|N\/A\b)\S (?:[^\S\r\n] \S )*?)?\s (?P<duplex>Full|N\/A)\b\s (?P<speed>[\d\w\/] )\s (?P<neg>[\w\/] )\s (?P<link_state>[\w] )\s (?P<flow_control>[\w\/] )(?:(?P<mode>[^\S\r\n] \w )(?:[^\S\r\n] (?P<vlans>[\d(),-] (?:\r?\n[^\S\r\n] [\d(),-] )*))?)?

See another regex 101 demo.