Re: to parse a string
- From: anno4000@xxxxxxxxxxxxxxxxxxxxxxx (Anno Siegel)
- Date: 28 Oct 2005 11:21:25 GMT
John W. Krahn <krahnj@xxxxxxxxx> wrote in comp.lang.perl.misc:
> Tassilo v. Parseval wrote:
> > Also sprach Tad McClellan:
> >
> >>cc <mmzzcc.c@xxxxxxxxx> wrote:
> >>
> >>>Given a string, e.g. "01010123", any sample code to scan it and then
> >>>find the "2" and "3" are not qualified in the string which requires
> >>>only "0" and "1"?
> >>
> >>The usual idiom for validating data is:
> >>
> >> anchor the beginning.
> >>
> >> anchor the ending.
> >
> > Why the anchoring?
> >
> >> write a regex in between that accounts for everything
> >> that you want to allow.
> >>
> >>
> >>print "'$str' is bad data\n" unless $str =~ /^[01]+$/;
> >
> > Or use tr:
> >
> > print "'$str' is bad data\n" if $str =~ tr/^01//c;
> ^
> Are you sure that caret is supposed to be there?
Yes, in Middle-High-Perl where double negation is the norm.
Anno
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- References:
- Re: to parse a string
- From: Tad McClellan
- Re: to parse a string
- From: Tassilo v. Parseval
- Re: to parse a string
- From: John W. Krahn
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