Leading Number Regex 2

[jriggs420]

Hi all. I'm looking for the regex that seeks out a leading whole number (1,2,3...30) optionally followed be a period, and removes it. My original attempt was

s/^[1-30]\.?//;

not working tho. Suggestions? TIA

A clever person solves a problem.
A wise person avoids it.

-- Einstein

 

[TonyGroves]

You might have to use something like:
[tt]
if($var+0>=1&&$var+0<=30)
{$var=~s/[0-9]+\.?//}
[/tt]

 

[ishnid]

[1-30] is looking for the range 1 .. 3 (i.e. 1,2,3) or a zero. This isn't the most elegant but should do the trick:

s/
  ^             # start of the string
   (?:          # begin a non-capturing group
      [12]?\d   # an optional 1 or 2, followed by a digit (i.e. 1 to 29)
      |         # or
      30        # thirty
   )            # close the non-capturing group
   \.           # followed by a dot
//x;         # replace with nothing

(the /x at the end of the regexp allows me to add comments as I have done above, otherwise the regexp engine would be trying to match all the whitespace in my expression too).

 

[TrojanWarBlade]

Nice work Ish.
You beat me to that one.
Very clear and consise though.
Excellent work.

A Star from the Trojan! (very rare things)



Trojan.

 

[duncdude]

Hi ish

Your regex would match a zero - on its own...

Sorry

Kind Regards
Duncan

 

[TrojanWarBlade]

Duncdude pointed out a minor error in your regex Ish.
You'll process a zero.
Maybe you might want to swap in something like this:

(?: [1-9] | [12]\d | 30 )

Trojan.

 

[ishnid]

You're right Dunc - how's this:

s/
  ^              # start of the string
   (?:           # begin a non-capturing group
      [12]?[1-9] # an optional 1 or 2, followed by a digit between 1 and 9 (i.e. 1-9, 11-19, 21-29
      |          # or
      [1-3]0     # 1, 2 or 3 followed by zero (i.e. 10, 20, 30)
   )             # close the non-capturing group
   \.            # followed by a dot
//x;             # replace with nothing

Cheers TWB - rare indeed! Your profile says it's the ninth you've given in this forum - I'm privileged.

 

[TrojanWarBlade]

LOL!

Another nice solution Ish.
excellent lateral thinking.
I'd consider giving you another start but that might devalue Trojan Star's a little too much! ;-)



Trojan.

 

[duncdude]

Poetry!

nice work ish! ;-)

Kind Regards
Duncan

 

[jriggs420]

Thanks all...I haven;t had a chance to test it out yet, but I was wondering if Ishnid's latest post will account for the optional dot (.)? Does simply adding a ? after the character in question make it optional?

Also what is 'd', I know it's dataset, but what does that mean? is '23' a dataset? What about 'word' or '23word'? Many thanks-
Joe

A clever person solves a problem.
A wise person avoids it.

-- Einstein

 

[ishnid]

Sorry, I missed that the dot at the end was optional - putting a '?' after it will indeed make it optional.

\d is a pre-defined character class - it matches any numeric character (i.e. 0-9). To define your own character classes, you enclose it in square brackets, e.g. [12] matches a '1' character or a '2' character.

 

[TrojanWarBlade]

I don't know.
I thought your work was good Ish.
Now it's been torn to pieces!.
Error after error.
I am SOOO dissapointed in you!!! ;-)


Trojan.

 

[ishnid]

Yeah well you still can't have your star back . . . so there

 

[TrojanWarBlade]

Nah, you keep it.
Trojan stars are very precious!



Trojan.

 

[ishnid]

I'll treasure it forever - it'll be like my own Phial of Galadriel.

 

[TrojanWarBlade]

Glad you're pleased with it!

Anyway, all joking aside, I did like your original post. It might not have been perfect but the concept was exactly what I would have liked to have posted.



Trojan.