On Jul 29, 12:09 pm, [EMAIL PROTECTED] (Jan-Henrik) wrote:
> On 29 juil, 17:40, [EMAIL PROTECTED] (Paul Lalli) wrote:
> > On Jul 29, 8:46 am, [EMAIL PROTECTED] (Jan-Henrik) wrote:
>
> Thank you very much for the detailed answer, I'll use it as a
> reference in the future.
> My case today: I just want to enter small numbers with a max of 4-5
> digits or so, nothing special. So it's enough to just make sure the
> input does not contain any letters...
Those two statements are a contradiction. One one hand, you say you
want the input to contain "small numbers with max of 4-5 digits."
Immediately, after that, you say "it's enough just to make sure the
input does not contain any letters". You seem to be operating under
the assumption that letters and numbers are the only possible inputs.
This is not true. As I replied to Aruna Goke elsewhere in this
thread, what do you expect to happen if someone gives you a string
containing "=-*&43# @8,>}" ?
> > > 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...
>
> > I don't know what you're trying to ask here. Please give us an
> > example of what you want to do - what the string will contain before
> > you do something to it, and what the string will look like afterwards.
>
> For example, if I read a string like this from a file:
> -----------------------------------------
> Cowmilk (l/h) 4.5023 Cows in Europe 4.5
> -----------------------------------------
> I want to "extract" (sorry for using substract in the first post) the
> 4.5023 from the string, how do I do that in a smart way? I need to do
> so simple calculations with that number... And the position in the
> string is not always the same, neither is the number of digits...
You look for the number, using whichever regexp from my original post
is most appropriate, and "capture" it using parentheses.
A very quick example:
#!/usr/bin/perl
use strict;
use warnings;
my $string = "Cowmilk (l/h) 4.5023 Cows in
Europe 4.5"
if ($string = /(\d+(?:\.\d+)?)/) {
my $number = $1;
print $number;
} else {
print "No floating point number found in '$string'\n";
}
__END__
For more information, check out the following documents, by running
these commands at your command line:
perldoc perlretut
perldoc perlre
perldoc perlreref
Paul Lalli
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