Jan-Henrik wrote:
> On 29 juil, 14:46, [EMAIL PROTECTED] (Jan-Henrik) wrote:
>> Dear Group,
>>
>> I'm new to Perl and I have a simple question:
>>
>> I ask for the entry of a number vie <STDIN>:
>>
>> ----------------------------------------
>> #!/usr/bin/perl -w
>> use strict;
>>
>> my $foo;
>> print "Enter number: ";
>> $foo = <STDIN>;
>> comp($foo);
>> ----------------------------------------
>>
>> Now I would like to check wether the user really entered a number and
>> not letters. What would a check like that look like? A regular
>> expression like this:
>> ----------------------------------------
>> unless ($foo =~ /[a-zA-Z\D+][^.][\D*]/ {...};
>> ----------------------------------------
>>
>> Is there an easier or more beautiful way?
>>
>> Also, how would I substract just a number from a string? Searched the
>> net for an example but didn't succeed, so sorry for asking a question
>> like that...
>>
>> Many thanks for your help!
>>
>> Kind regards,
>>
>> Jan-Henrik
>
> I'm stupid, sorry.
> It's as easy as this:
> ----------------------------------------
> unless ($foo =~ /[a-zA-Z]/ {...};
> ----------------------------------------
> :-)
No, it's not.
All the punctuation passes that test as Paul has pointed out, and do you want to
stop them from entering 1E6 fpor one million?
If you're after purely numeric input you can (after chomping the input) write
unless ($input =~ /\D/) {
:
}
but it's still a bit draconian to disallow leading and trailing whitespace.
Rob
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