Variable Format

[pani765]

Hello,

I am new to perl. So i was wondering if anyone can tell what the following line mean.


$event_id =~ /^(\d+)(_\d)?(\d*)$/o;
$event_id = "$1$2$3";

if i want event_id to in the format of $id_0_$i where i is 0 to x, how would i change those line.

Thank You,

Roj

 

[duncdude]

$event_id =~ /^(\d+)(_\d)?(\d*)$/o;

/ start of pattern match
^ caret - match at beginning of line
( in this case, as it is soon to be followed by ), means store result... as $1
\d+ match at least one digit (\d = digit, + = at least one)
(_\d)? an underscore, a digit, report match (?) whether found or not, store as $2 (parentheses)
(\d*) match zero or more digits, store result as $3
$ match end of line
/ end of pattern match
0 compiles the pattern only once (will speed it up)

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$event_id = "$1$2$3";

assign $event_id to the stored matches as mentioned above - in the order match1 + match2 + match3

I'll have a think about the second part of your question

Regards
Duncan