Re: Regular expression: How to determine wether entry is a number?

[janhorstmann@xxxxxx (Jan-Henrik)]

On 29 juil, 14:46, janhorstm...@xxxxxx (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]/ {...};
----------------------------------------
:-)