Re: Identifying the position of match using regular expressions

You can use the index function. For example:

>perl -Mstrict -we "my $s = q[ABCDFEFFAA]; print index($s, $1), qq[\n]
+ if $s =~ /(AA)/;"
8
[download]

Hope that helps,

Athanasius <°(((>< contra mundum

Comment on Re: Identifying the position of match using regular expressions Download Code

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Re^2: Identifying the position of match using regular expressions by Anonymous Monk on Sep 15, 2012 at 06:21 UTC
Thank you. But it gives some error like this syntax error at -e line 1, near "my =" syntax error at -e line 1, near "index(," Execution of -e aborted due to compilation errors. More over i have a large data set which cannot be worked out with command line. i just gave an example of what i want. my actual data it has to identify the pattern ASHGFDF in a substring of 250 characters. i can post the pgm if needed	[reply]
Re^3: Identifying the position of match using regular expressions by Athanasius (Archbishop) on Sep 15, 2012 at 06:43 UTC
When running a Perl one-liner on a non-Windows system you will probably need to change the double quotes (`"`) to single quotes (`'`). Check the requirements of the particular shell you’re using to run `perl`. But I only used a one-liner as a quick way to demonstrate the technique you can use. Once you have the match (say, in `$1`), you can find where in the original string it matched using index. This will work regardless of the number of characters in the string or in the match. Note that the values returned by `index` are zero-based; that is, if the match begins on the first character of the original string, `index` returns zero. If the substring is not found within the original string, `index` returns -1. Athanasius <°(((>< contra mundum	[reply]