Beefy Boxes and Bandwidth Generously Provided by pair Networks
Perl: the Markov chain saw
 
PerlMonks  

comment on

( #3333=superdoc: print w/replies, xml ) Need Help??
Here is another approach. It keeps the blank lines after the text (if you need to separate records like they are in the testlines.txt file).

It reads the file to be parsed from the command line following the program invocation. ( perl regex.pl testlines.txt )

It also places the local statement and the code inside a block to limit the changes to $/ to the block. Although this is not necessary for this small program, in a larger program, this will restore $/ to \n after the block is finished for any code that could follow.

#!/usr/bin/perl use strict; use warnings; @ARGV == 1 or print "Usage: perl $0 testlines.txt\n" and exit; { local $/ = "\n\n"; print grep /\b(?:third|four)\b/i, <>; }

My command prompt:

C:\Old_Data\perlp>perl test3.pl testlines.txt This is line one. Line Two is this. Third line starts here. This is line four.

In reply to Re: Question about regex. by Cristoforo
in thread Question about regex. by that_perl_guy

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post; it's "PerlMonks-approved HTML":



  • Are you posting in the right place? Check out Where do I post X? to know for sure.
  • Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:
    <code> <a> <b> <big> <blockquote> <br /> <dd> <dl> <dt> <em> <font> <h1> <h2> <h3> <h4> <h5> <h6> <hr /> <i> <li> <nbsp> <ol> <p> <small> <strike> <strong> <sub> <sup> <table> <td> <th> <tr> <tt> <u> <ul>
  • Snippets of code should be wrapped in <code> tags not <pre> tags. In fact, <pre> tags should generally be avoided. If they must be used, extreme care should be taken to ensure that their contents do not have long lines (<70 chars), in order to prevent horizontal scrolling (and possible janitor intervention).
  • Want more info? How to link or or How to display code and escape characters are good places to start.
Log In?
Username:
Password:

What's my password?
Create A New User
Chatterbox?
and the web crawler heard nothing...

How do I use this? | Other CB clients
Other Users?
Others meditating upon the Monastery: (7)
As of 2021-06-16 13:50 GMT
Sections?
Information?
Find Nodes?
Leftovers?
    Voting Booth?
    What does the "s" stand for in "perls"? (Whence perls)












    Results (74 votes). Check out past polls.

    Notices?