Interesting and thoughtful question. You use "(" and ")" to mark (remember) a pattern and recall the remembered pattern with "\" followed by a single digit (back reference).
In your particular case, "(.)\1" means remember a character and recall the character.
You can extend this method to find words with multiple double letters. '(.)\1(.)\2(.)\3' will match any word with three double letters, e.g. bookkeeper.
The logic can be extended further to find "double" words, like cancan and booboo:
or repeated words, like "the the":
and so on and so on...... (three repeated words)
Hi,
Can anyone help me to find regular expression for the following in Perl?
"The string can only contain lower case letters (a-z) and no more than one of any letter."
For example: "table" is accepted, whether "dude" is not.
I have coded like this:
$str = "table";
if ($str =~ m/\b()\b/) {... (4 Replies)
I have got numbers like
l255677
l376039
l188144
l340482
l440700
l254113
to match the numbers starting with '13' what would be the regex
=~/13(.*)/ =======>This is not working ....
But for user123,user657
regex =~/user(.*)/ ========>works
Thanks for help..!! (7 Replies)
I am having trouble parsing rpm filenames in a shell script.. I found a snippet of perl code that will perform the task but I really don't have time to rewrite the entire script in perl. I cannot for the life of me convert this code into something sed-friendly:
if ($rpm =~ /(*)-(*)-(*)\.(.*)/)... (1 Reply)
Hi,
I get the following when I cat a file *.log
xxxxx
=====
dasdas gwdgsg fdsagfsag agsdfag
=====
random data
=====
My output should look like :
If the random data after the 2nd ==== is null then OK should be printed else
the random data should be printed.
How do I go about this... (5 Replies)
HI,
I'm new to perl and need simple regex for reading a file using my perl script.
The text file reads as -
filename=/pot/uio/current/myremificates.txt
certificates=/pot/uio/current/userdir/conf/user/gamma/settings/security/... (3 Replies)
Hi Guys
I have the following regex
$OSRELEASE = $1 if ($output =~ /(Mac OS X (Server )?10.\d)/);
output is currently
Mac OS X 10.7.5
when the introduction of Mac 10.8 output changes to
OS X 10.8.2
they have dropped the Mac bit so i changed the regex to be (2 Replies)
Hello,
I'm trying to get a quick help on regex since i'm not a regular programmer.
Below is the line i'm trying to apply my regex to..i want to use the regex in a for loop and this line will keep on changing.
subject=... (4 Replies)
Could anyone please make me understand how the ?= works below ..
After executing this I am getting the same output.
$string="I love chocolate.";
$string =~ s/chocolate(?= ice)/vanilla/;
print "$string\n"; (2 Replies)
I am not a big expert in regex and have just little understanding of that language.
Could you help me to understand the regular Perl expression:
^(?!if\b|else\b|while\b|)(?:+?\s+){1,6}(+\s*)\(*\) *?(?:^*;?+){0,10}\{
------
This is regex to select functions from a C/C++ source and defined in... (2 Replies)
Experts -
I found a script on one of the servers that I work on and I need help understanding
one of the lines.
I know what the script does, but I'm having a hard time understanding the grouping.
Can someone help me with this?
Here's the script...
#!/usr/bin/perl
use strict;
use... (2 Replies)
Perl::Critic::Policy::BuiltinFunctions::ProhibitStringySUser(Contributed Perl DocumPerl::Critic::Policy::BuiltinFunctions::ProhibitStringySplit(3)NAME
Perl::Critic::Policy::BuiltinFunctions::ProhibitStringySplit - Write "split /-/, $string" instead of "split '-', $string".
AFFILIATION
This Policy is part of the core Perl::Critic distribution.
DESCRIPTION
The "split" function always interprets the PATTERN argument as a regular expression, even if you specify it as a string. This causes much
confusion if the string contains regex metacharacters. So for clarity, always express the PATTERN argument as a regex.
$string = 'Fred|Barney';
@names = split '|', $string; #not ok, is ('F', 'r', 'e', 'd', '|', 'B', 'a' ...)
@names = split m/[|]/, $string; #ok, is ('Fred', Barney')
When the PATTERN is a single space the "split" function has special behavior, so Perl::Critic forgives that usage. See "perldoc -f split"
for more information.
CONFIGURATION
This Policy is not configurable except for the standard options.
SEE ALSO
Perl::Critic::Policy::ControlStrucutres::RequireBlockGrep
Perl::Critic::Policy::ControlStrucutres::RequireBlockMap
AUTHOR
Jeffrey Ryan Thalhammer <jeff@imaginative-software.com>
COPYRIGHT
Copyright (c) 2005-2011 Imaginative Software Systems. All rights reserved.
This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself. The full text of this license
can be found in the LICENSE file included with this module.
perl v5.16.3 2014-06-09 Perl::Critic::Policy::BuiltinFunctions::ProhibitStringySplit(3)