On Fri, Oct 19, 2012 at 3:42 PM, Girish Venkatachalam <
[email protected]> wrote:
> 1)
>
> $ cat i.pl
> for(<>) {
> print uc;
> }
>
> This is a simple tr(1) implementation.
>
> These two lines and a closing brace do what tr does to
> translate from lower case to upper case.
>
> You run like this
>
> $ perl i.pl
> foo just trying
> <ctrl-d>
>
> You will get upper case results.
>
> 2)
>
> $ cat i.pl
> for(<>) {
> print if /peter/;
> }
>
> Use same technique for running. You will only get lines that contain peter.
>
> Now the / / operator is actually a regex match pattern in perl.
>
> You can match for literal words like above or actually regex classes
> like digits like this:
>
> 3)
>
> $ cat i.pl
> for(<>) {
> print if /\d/;
> }
>
>
> Now you will get lines that contain digits 0 to 9. This also will work.
>
> print if /[0-9/;
>
> Another interesting sample.
>
> 4)
> $ cat i.pl
> for(<>) {
> print $& if /\d+/;
> }
>
> This not only prints the match but also matches multiple digits.
>
> That is what \d+ does.
>
> regex is a complex topic and all perl code you find will go through a
> file line by line and look for matches.
>
> So remember the diamond operator <> for reading a file line by line and
> the regex match / / operator.
>
> You can easily do an if else condition match and execute code in perl using
> regexes.
>
> This finds plenty of practical use.
>
> I will come up with some practical instances tomorrow.
>
> -Girish
>
>
> --
> Gayatri Hitech
> http://gayatri-hitech.com
> _______________________________________________
> ILUGC Mailing List:
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>
I use this mostly http://gskinner.com/RegExr/
--
Regards,
Balasubramaniam Natarajan
www.etutorshop.com/moodle/
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