Search and Extract from String

madbee has asked for the wisdom of the Perl Monks concerning the following question:

Hello - Perl newbie here looking for some help in string manipulation! I have a String which can either be with the "-" or without that character. String is: "This is a design-controlled string". (OR) "This is a design controlled string"; In either case, I have to extract the word "design" if Controlled is found. To determine if Controlled exists, I have the below. So, inside the IF,I'm thinking this is what I need to do.

   if ($title_ele =~ m/controlled/i)
  {
[download]

#controlled exists

#Find the position where "controlled" starts in string

$pos = index($title_ele,$controlled_key);

#Extract everything from <start of string> till <start of controlled>

#Split the remaining string by space.

#check if last word is "-". If it is, extract the second last word,which will be "design".

Is this the right approach? If so, how can I implement it using Perl? Alternately, is there an easier way that I can extract the word "design" from a string if "controlled" exists? Thanks much in advance, madbee

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Re: Search and Extract from String by Laurent_R (Canon) on Jun 29, 2013 at 09:38 UTC
Or simply: `print $1 if $string =~ /(\w+)[- ]controlled/;`	[reply] [d/l]
Re^2: Search and Extract from String by madbee (Acolyte) on Jun 29, 2013 at 13:18 UTC
Thanks, so much! This worked. Saved me tons of lines of code had I gone with my approach	[reply]
Re: Search and Extract from String by hdb (Monsignor) on Jun 29, 2013 at 08:25 UTC
It is much easier to build a regex, similar to the one you use to find "controlled", that looks for the sequence of the words "design" and "controlled" with either a space or a hyphen in between. A regex to match one character or another can be constructed using the pipe character. For example, `(a\|b)` will match a or b,	[reply] [d/l] [select]
Re: Search and Extract from String by poj (Abbot) on Jun 29, 2013 at 08:50 UTC
You can a match and capture part of the string with brackets(). The captured part is stored in the variable $1. For example ; `#!perl use strict; while (<DATA>){ # capture word with () # [- ] character is space or dash if (m/(design\|otherword)[- ]controlled/i){ # captured word is in $1 print "Word < $1 >found in $_"; } else { print "No word found in $_"; } } __DATA__ This is a design controlled string This is a design-controlled string This is a controlled design string This is an otherword-controlled string` [download] poj	[reply] [d/l]
Re: Search and Extract from String by 2teez (Vicar) on Jun 29, 2013 at 08:50 UTC
Hi madbee, There are several ways you can use to make this happen. Though following your "outline" could make it make ( I didn't try it), but using regex could also do this: `use warnings; use strict; while(<DATA>){ if(/controlled/i){ if(/(?<=a)\s(.+?)-?(?=controlled)/i){ #NOTE HERE print $1,$/; } } } __DATA__ This is a design-controlled string This is a design controlled string` [download] ..produces... `design design` [download] NOTE: This might not be a generic solution, simply because am using OP data. Please see Using Look-ahead and Look-behind If you tell me, I'll forget. If you show me, I'll remember. if you involve me, I'll understand. --- Author unknown to me	[reply] [d/l] [select]
Re: Search and Extract from String by ww (Archbishop) on Jun 29, 2013 at 15:18 UTC
Untrue assumption in the last "#" note: " ... #Split the remaining string by space. #check if last word is "-". If it is, extract the second last word,which will be "design"." Test case: `perl -E "my $s = 'This is a design-controlled'; my @arr=split / /, $s; for $_(@arr) { say $_;}"` Output (note that last word is NOT a stand-alone hyphen/dash): `This is a design-controlled` [download] And the "second last word" is "a" If you didn't program your executable by toggling in binary, it wasn't really programming!	[reply] [d/l] [select]