Problem replacing the string

ramesh54

Hello All,

I have a test file z.txt with following lines

*transformation
X Y Z
10 20 30

Finally i need to have a the same text files as follows,

*transformation
X Y Z
50 60 80

When i run the code in windows, I am getting the error
Global symbol requires explicit package.

Could you please let me know what is wrong .

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#!\usr\bin\perl 

use warnings;

use strict;

open IN, "z.txt";  

@file = <IN>;

$count = 0; 

foreach $file (@file){ 

if ($file =~ /\*transformation/){ 

$count = $count + 1; 

} 

if ( $count == 1 ){ 

$count = $count + 1; 

} 

if ( $count == 2 ){ 

$file =~ s/ 10 20 30/50 60 80/g; 

print IN $file; 

$count = 0;

last; 

} 

} 

close IN;

Looking forward to your response.

Ramesh

KevinADC

when you use the "strict" pragma you have to declare the private variables properly. You do that with "my" for the most part.

http://perldoc.perl.org/perlsub.html...ables-via-my()

ramesh54

Hi kevin,

Still i am getting the same error message. I have include 'my' in the program.

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#!\usr\bin\perl 

use warnings;

use strict;

open IN, "z.txt";  

my @file = <IN>;

my $count = 0; 

foreach $file (@file){ 

if ($file =~ /\*transformation/){ 

$count = $count + 1; 

} 

if ( $count == 1 ){ 

$count = $count + 1; 

} 

if ( $count == 2 ){ 

$file =~ s/ 10 20 30/50 60 80/g; 

print IN $file; 

$count = 0;

last; 

} 

} 

close IN;

KevinADC

foreach my $file (@file){

numberwhun

I have now fixed your code tags twice and this is your warning. Code tags are not an option, they are required to surround any code that you place in a post in the forums.

Use them please, or other actions will be taken.

Regards,

Moderator

ramesh54

Now the program runs without error. But the output is different.

It prints the output as follows

*transformation
x y z
10 20 30
*transformation

But i wanted to replace 10 20 30 by 50 60 80 without editing the other lines. What could be the possible error.

KevinADC

Either edit the file inplace or edit the array (@file) and overwrite the existing file (IN) with the contents of @array.

ramesh54

Hi Kevin,

I would like to keep the input file as it is. What i am unable to understand is that , in my loop i skip the first 2 lines and then i replace the text in the 3 rd line and print only the third line. But the output I get is for the first line. What is wrong with my loop formation?

nithinpes

Hi Kevin,

I would like to keep the input file as it is. What i am unable to understand is that , in my loop i skip the first 2 lines and then i replace the text in the 3 rd line and print only the third line. But the output I get is for the first line. What is wrong with my loop formation?

Well, if you want to keep the input file as it is and to write modified output to a different file, you need to open another file for writing.
But then, you will not get the required output because of the logical error in your script.
You are not skipping to the third line in your script, but successively incrementing a variable $count and printing $file. The $file will still be referring to line containing *transformation.

You can try this:

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#!\usr\bin\perl 

use warnings;

use strict;

open IN, "z.txt";  

open OUT,">out.txt";
 
while (<IN>){ 

my $file = $_;

if ($file =~ /\*transformation/){ 

print OUT $file; #print the line

my $dump=<IN>; # skip to next line

print OUT $dump;

$file=<IN>; # skip to the required line

} 
 
$file =~ s/10 20 30/50 60 80/g; 

print OUT $file; 
 
} 

close IN;

close OUT;

ramesh54

Hi Kevin,

Great! your code works well and I wanted to overwrite it in my input file itself and so i have corrected the mode to +< in output.
Thanks!

KevinADC

Hi Kevin,

Great! your code works well and I wanted to overwrite it in my input file itself and so i have corrected the mode to +< in output.
Thanks!

It was the easiest code I never wrote..... ;)

alampally

HI Ramesh,

Have a look at the following sample code and you can replace what I have placed for you....

Snippet#1

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$string1 = "I love to eat apples all day. I can eat apples every day! Apples are yummy!";

$string1 =~ s/apples/oranges/g;

print "The resulting value is : $string1 \n";

Snippet#2

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$string1 = "today is the best day of all";

if ($string1 =~ tr/thed/abc/){

print "String1 now contains $string1. \n";

} else {

print "No match found.: \n";

}

Either of the snippet will replace a string in your file.....

Good Luck,

Write me for any help in C, C++, Perl, PHP and UNIX related stuff. I will answer you with in the time with free of cost.

Rammohan Alampally,
HP Technologies
Bangalore

KevinADC

Either of the snippet will replace a string in your file.....

That is not accurate. The snippets will replace the search pattern with the replacement pattern in the string. He will need to use Tie::File or other method to update the lines of the file. Your code only processes a string, which is not the same as updating a line in a file.

Problem replacing the string

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