Say you have the string "abcdefghi".
The positions in the string are:
a b c d e f g h i
^ ^ ^ ^ ^ ^ ^ ^ ^ ^
0 1 2 3 4 5 6 7 8 9
If you have the regular expression:
/(de)/
Then the match starts at position 3, moves forward two characters, and
ends at position 5, where the next match, if any, will start.
If it stopped at position 4 then it would only match 1 character.
If you want to explore all the gory details of regular expressions
then get the book _Mastering Regular Expression_ by Jeffrey E. F. Friedl:
http://www.oreilly.com/catalog/regex3/index.html
John
Hi, John
Took your advice and start to read 'Mastering regular expression' by
Jeffrey E.F.Friedl,
Can you explain below further?
on page, 205
push(@fields, $+) while $text =~ m{
"([^\"\\]*(?:\\.[^\"\\]*)*)",? #standard quoted string(with
possible comma)
| ([^,]+),? #or up to next comman(with
possible comma)
| ,
}gx;
I am not totally understanding how the first line is matching standard
quoted string.
I understand " " in beginning and end and option ,? at the very end.
now why ---> [^\"\\]* , should read anything except \ and " and \\ ?
why?
and then followed by pretty much samething(in grouping only option ?:)
followed by \\ ?? and samething?
How is that suppose to match quoted string? such as "hi, how are you",
Also, how does this work?
defined($1) ? $1 : $3; This ternary reads if $1 is true, then test to
see if $1 is defined? IF $1 is not true, then $3 is defined?(or ??)
--
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]
http://learn.perl.org/
