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Text file manipulation with perl

huskysv
New User

Oct 29, 2013, 1:50 AM

Post #1 of 4 (239 views)

Text file manipulation with perl	Can't Post

Hi Perl Gurus,

I am new to perl and having a bit of a hard time with manipulating a text file.

In this scenario I have two text files.

Text1.txt - which contains some text

Text2.txt - this is whats inside Text2.txt

Code

<section 1></section1>   <section2></section2>

What I need the perl script to do is read Text2.txt and then locate <section1> and right after that insert the text from Text1.txt in between the <section1> and </section1> tags.

Can anybody help out with that? I know how to do it in other languages but am very lost in perl

BillKSmith
Veteran

Oct 29, 2013, 7:22 AM

Post #2 of 4 (229 views)

Re: [huskysv] Text file manipulation with perl [In reply to]	Can't Post

There are many ways to do this in Perl. The choice among them depends upon many factors which you did not tell us. How long are the files? Are the <section1> and </section1> tags always on the same line? Is Text2.txt an HTML document? Is it a template that never changes?

One approach that should always work is to slurp Text1 into a single string $string1. Slurp Text2 into $string2. Use a regular expression to replace the gap in $string1 with the contents of $string2. Use positive lookahead and positive lookbehind assertions to match the tags, but not include them in the matched text. (Refer to documentation on extended regular expressions)
Good Luck,
Bill

Laurent_R
Enthusiast / Moderator

Oct 29, 2013, 10:52 AM

Post #3 of 4 (224 views)

Re: [huskysv] Text file manipulation with perl [In reply to]	Can't Post

I agree with Bill, we need more information, such as file size and the format of file1.Can you please provide a sample?

BillKSmith
Veteran

Oct 29, 2013, 3:47 PM

Post #4 of 4 (214 views)

Re: [huskysv] Text file manipulation with perl [In reply to]	Can't Post

Here is a complete perl program that does the substitution that I described in my last post. Note that the /x option allowed me to add whitespace and comments. The /m and /s options are not needed in this simple example. They do no harm in this case and they allow the substitution to work on a multiline string.

Code

use strict; 
use warnings; 
my $string1 = 'Insert this text in document'; 
my $string2 = 'stuff <section1></section1> more stuff <section2></section2>'; 
 
$string2 
    =~ s{ 
        (?<=  <section1>  )     # Look behind 
        .*                      # Match anything between tags 
        (?=  </section1>  )     # Look ahead 
    } 
    {$string1}xms;              # Replacement string 
 
print $string2, "\n";

Good Luck,
Bill

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