topic Re: Reg Exp. Problem in Operating System - HP-UX

Reg Exp. Problem

Joshila — Wed, 30 Jun 2004 06:56:09 GMT

I need to write a regular expression which will match a string value for N's and T's but not a combination like NTNTNTN

This expression is what i wrote

[N*T*]$

Acceptable values of string
N
NNNNN.... any number of N's
T
TTTTTT ... any number of T's
N N N N there can be spaces inbetween
T T T T ...
but NOT something NTNTNTN or TNTNTNT
but the expression above is matching this combination tooo ...

Can anyone help me solve this?

Re: Reg Exp. Problem

Elmar P. Kolkman — Wed, 30 Jun 2004 07:08:13 GMT

Solution I would use: {N+|T+}$
It depends on the program you use if this is a supported regex. And use + instead of *, because you don't want to match empty patterns.

Re: Reg Exp. Problem

Elmar P. Kolkman — Wed, 30 Jun 2004 07:11:52 GMT

For egrep:
egrep 'N+$|T+$'

Re: Reg Exp. Problem

Elmar P. Kolkman — Wed, 30 Jun 2004 07:15:19 GMT

Sorry, missed one thing...
Should be:
egrep '^N+$|^T+$'