Contributed by Anonymous Monk
on May 05, 2000 at 06:06 UTC
> data formatting
For example, given
$string = "abe[123955785adasd]jdjajd";
I want to extract the substring between the [ and ] characters, and store it in another variable.
|Answer: How to extract a delimited substring?|
contributed by btrott
my $string = "abe[123955785ada]sdjdjajd";
if ( $string =~ /\[(.*?)\]/ )
my $inside = $1;
print $inside, "\n";
The string inside the brackets is in $inside.
The ( and ) around the .*? are "grouping parentheses";
they tell perl's regular expression engine to capture whatever
it matches between them and store it in a special variable.
The variable name will be a digit corresponding to the
parenthesis group — $1 for the first group,
$2 for the second group, etc. —
counting '('s from the left.
So, in this case, perl captures what it finds between the
[ and ] and stores that string in $1.
And what does it match? In this case, we've told it to
match any character ("."), repeated 0 or more times ("*"),
in a non-greedy manner ("?"). This last is best illustrated
Say your original string was
There are two sets of [/]-delimited strings in there.
Without the "?" in the regular expression, perl would match from
the first [ to the last ], putting the following
Most likely, this isn't what you want, so we put in the
non-greedy modifier to make perl do what you want.
By the way, I said that "." matches any character; this
isn't strictly true. It usually doesn't match carriage
returns; if you want it to match carriage returns as well, add
the /s modifier at the end of the regular expression.
For more information, see perlre. It explains all of this and more.
Please (register and) log in if you wish to add an answer
Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
Read Where should I post X? if you're not absolutely sure you're posting in the right place.
Please read these before you post! —
Posts may use any of the Perl Monks Approved HTML tags:
You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
- a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
Link using PerlMonks shortcuts! What shortcuts can I use for linking?
See Writeup Formatting Tips and other pages linked from there for more info.
| & || & |
| < || < |
| > || > |
| [ || [ |
| ] || ] ||