Regex, oh how I love thee...let me count all thy permutations...

[Joel]

OK so it has been awhile since I had to program anything in regular expression. Now I have to validate that the end user enters a valid IP address. I know how to implement the method that returns the regular expression, and I use the preset character code:

\d\d\d[.]\d\d\d[.]\d\d[.]\d\d

However, the last 3 octets MIGHT only be 1 digit...how do you suppose I should compensate for that possibility? Thanks for your help!

[JosAH]

OK so it has been awhile since I had to program anything in regular expression. Now I have to validate that the end user enters a valid IP address. I know how to implement the method that returns the regular expression, and I use the preset character code:

\d\d\d[.]\d\d\d[.]\d\d[.]\d\d

However, the last 3 octets MIGHT only be 1 digit...how do you suppose I should compensate for that possibility? Thanks for your help!

A range? i.e. x{1,3} means 'x one to three times'. b.t.w. those aren't permutations.

kind regards,

Jos

[Joel]

A range? i.e. x{1,3} means 'x one to three times'. b.t.w. those aren't permutations.

kind regards,

Jos

Kind regards to YOU , good sir!

Lamentably I chose the wrong word. They aren't permutations at all. Combinatorics?

[JosAH]

Kind regards to YOU , good sir!

Lamentably I chose the wrong word. They aren't permutations at all. Combinatorics?

Nope, they aren't combinations either, sorry for that ;-) Example:

C(3, 1) == a, b, c
C(3, 2) == ab, ac, bc
C(3, 3) == abc
P(3) == abc, acb, bac, bca, cab, cba

kind regards,

Jos