RE: Regarding reg. exp.

[Irfan Sayed]

Thanks really

-----Original Message-----
From: Rob Dixon [mailto:rob.dixon@xxxxxxx]
Sent: Tuesday, October 14, 2008 6:31 PM
To: Perl Beginners
Cc: Sayed, Irfan (Cognizant)
Subject: Re: Regarding reg. exp.

Irfan.Sayed@xxxxxxxxxxxxx wrote:
> From: Rob Dixon [mailto:rob.dixon@xxxxxxx]
>> Irfan.Sayed@xxxxxxxxxxxxx wrote:
>>>
>>> I have a string and I need to parse that string to check whether it
is
>>> in required format or not. I have a Perl script which ask for user
>>> input. I have mentioned in the Perl script that input should be in
the
>>> following format.
>>>
>>> For example:-  1,2,3 OR 1 2 3
>>>
>>> Which means that delimiter between these figures should be comma OR
>>> space. No any other character. I need all users to adhere that and
if
>>> they not then they should exit.
>>>
>>> Can somebody please give me reg. exp. which can be used to parse the
>>> string and check whether comma OR space is there or not as a
delimiter
>>> and it should contain only numeric not alphabets.
>>
>> It is very draconian to require exactly one space or comma as
>> separators. However this will do what you ask.
>>
>> Rob
>>
>>
>> use strict;
>> use warnings;
>>
>> my $re = qr/^
>>   \d+
>>   (?:
>>    (?:,\d+)* | (?: \d+)*
>>   )
>> $/x;
>>
>> chomp (my $input = <>);
>>
>> if ($input =~ $re) {
>>   print "ok\n";
>> }
>> else {
>>   print "invalid\n";
>> }
>
> if ($trig_np =~ m/\d,{1}\d|\d\s{1}\d/)
>
> this what I did.

That is useless. If I typed

--=NONSENSE9 9NONSENSE=--

it would be accepted as valid. My code with Ruud's correction is the
simplest
way to do what you describe. Like this


  my $re = qr/^
    \d+
    (?:
      (?:,\d+)* | (?:[ ]\d+)*
    )
  $/x;

If you expect only single-digit numbers then replace '\d+' with '\d'
throughout.
If you only expect 1 through 9 then replace them with [1-9] instead.

Rob

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