comment on

One possible way is:

#!/usr/bin/perl
use strict;
use warnings;

use IO::All;
use Data::Dumper;
use feature 'say';

my @lines = io('file.txt')->chomp->slurp;
print Dumper \@lines;

for my $i (0 .. $#lines) {
    if ($lines[$i] =~ /operating_conditions/) {
    # Insert at position 12, replace 0 elements.
    splice @lines, $i + 5, 0, 'default_operating_conditions : "AB0.5v4
+5c" ;';
    last; # break loop
    }
    next;
}

print Dumper \@lines;

__END__

$ perl test.pl
$VAR1 = [
          'library(and_gate) {',
          '  delay_model : table_lookup ;',
          '  date : "Fri Mar 15 03:44:39 " ;',
          '  time_unit : 1ms ;',
          '  voltage_unit : 1V ;',
          '  current_unit : 1A ;',
          '',
          '  operating_conditions       ("AB0.5v45c") {',
          '    process : 1 ;',
          '    temperature : 45 ;',
          '    voltage : 0.5 ;',
          '  }',
          '',
          '  input_voltage(default) {',
          '    vi : 0 ;',
          '    vh : 0.5 ;',
          '    vim : 0 ;',
          '    vin : 0.5 ;',
          '  }',
          '',
          '}'
        ];
$VAR1 = [
          'library(and_gate) {',
          '  delay_model : table_lookup ;',
          '  date : "Fri Mar 15 03:44:39 " ;',
          '  time_unit : 1ms ;',
          '  voltage_unit : 1V ;',
          '  current_unit : 1A ;',
          '',
          '  operating_conditions       ("AB0.5v45c") {',
          '    process : 1 ;',
          '    temperature : 45 ;',
          '    voltage : 0.5 ;',
          '  }',
          'default_operating_conditions : "AB0.5v45c" ;',
          '',
          '  input_voltage(default) {',
          '    vi : 0 ;',
          '    vh : 0.5 ;',
          '    vim : 0 ;',
          '    vin : 0.5 ;',
          '  }',
          '',
          '}'
        ];
[download]

Update: I have hard-coded the data but you can do the parsing. My approach is to read the file in an array so you can know the exact position of the line that you want to alter. Next step insert a new line without altering the array using splice.

Sample of code to split string and insert it:

#!/usr/bin/perl
use strict;
use warnings;

use IO::All;
use Data::Dumper;
use feature 'say';

my @lines = io('file.txt')->chomp->slurp;
print Dumper \@lines;

for my $i (0 .. $#lines) {
    if ($lines[$i] =~ /operating_conditions/) {
    # split line based on white space
    my @elements = split /\s+/, $lines[$i];
    # remove first and last character of the string
    $elements[2] =~ s/^.(.*).$/$1/;
    # Insert string at position 12, replace 0 elements.
    splice
        @lines,
        $i + 5,
        0,
        "default_".$elements[1]." : ".$elements[2]."";
    last; # break loop
    }
    next;
}

print Dumper \@lines;

__END__

$ perl test.pl
$VAR1 = [
          'library(and_gate) {',
          '  delay_model : table_lookup ;',
          '  date : "Fri Mar 15 03:44:39 " ;',
          '  time_unit : 1ms ;',
          '  voltage_unit : 1V ;',
          '  current_unit : 1A ;',
          '',
          '  operating_conditions       ("AB0.5v45c") {',
          '    process : 1 ;',
          '    temperature : 45 ;',
          '    voltage : 0.5 ;',
          '  }',
          '',
          '  input_voltage(default) {',
          '    vi : 0 ;',
          '    vh : 0.5 ;',
          '    vim : 0 ;',
          '    vin : 0.5 ;',
          '  }',
          '',
          '}'
        ];
$VAR1 = [
          'library(and_gate) {',
          '  delay_model : table_lookup ;',
          '  date : "Fri Mar 15 03:44:39 " ;',
          '  time_unit : 1ms ;',
          '  voltage_unit : 1V ;',
          '  current_unit : 1A ;',
          '',
          '  operating_conditions       ("AB0.5v45c") {',
          '    process : 1 ;',
          '    temperature : 45 ;',
          '    voltage : 0.5 ;',
          '  }',
          'default_operating_conditions : "AB0.5v45c" ;',
          '',
          '  input_voltage(default) {',
          '    vi : 0 ;',
          '    vh : 0.5 ;',
          '    vim : 0 ;',
          '    vin : 0.5 ;',
          '  }',
          '',
          '}'
        ];
[download]

Update 2: All the commends together in one solution:

#!/usr/bin/perl
use strict;
use warnings;

use IO::All;
use Data::Dumper;

my @lines = io('file.txt')->chomp->slurp;

for my $i (0 .. $#lines) {
    if ($lines[$i] =~ /operating_conditions/) {
    # split line based on white space
    my @elements = split /\s+/, $lines[$i];
    # remove first and last character of the string
    $elements[2] =~ s/^.(.*).$/$1/;
    # Insert string at position 12, replace 0 elements.
    splice
        @lines,
        $i + 5,
        0,
        "  default_".$elements[1]." : ".$elements[2]."";
    last; # break loop
    }
    next;
}

# print Dumper \@lines;
io('out.txt')->appendln($_) for @lines;

__END__

$ perl test.pl
$ cat out.txt
library(and_gate) {
  delay_model : table_lookup ;
  date : "Fri Mar 15 03:44:39 " ;
  time_unit : 1ms ;
  voltage_unit : 1V ;
  current_unit : 1A ;

  operating_conditions       ("AB0.5v45c") {
    process : 1 ;
    temperature : 45 ;
    voltage : 0.5 ;
  }
  default_operating_conditions : "AB0.5v45c"

  input_voltage(default) {
    vi : 0 ;
    vh : 0.5 ;
    vim : 0 ;
    vin : 0.5 ;
  }

}
[download]

Update 3: Adding a better (more strict) regex to the solution:

#!/usr/bin/perl
use strict;
use warnings;

use IO::All;
use Data::Dumper;

my @lines = io('file.txt')->chomp->slurp;

for my $i (0 .. $#lines) {
    if ($lines[$i] =~ m/\s\soperating_conditions*/) {
    # split line based on white space
    my @elements = split /\s+/, $lines[$i];
    # remove first and last character of the string
    $elements[2] =~ s/^.(.*).$/$1/;
    # Insert string at position 12, replace 0 elements.
    splice
        @lines,
        $i + 5,
        0,
        "  default_".$elements[1]." : ".$elements[2]." ;";
    last; # break loop
    }
    next;
}

# print Dumper \@lines;
io('out.txt')->appendln($_) for @lines;

__END__

$ perl test.pl
$ cat out.txt
library(and_gate) {
  delay_model : table_lookup ;
  date : "Fri Mar 15 03:44:39 " ;
  time_unit : 1ms ;
  voltage_unit : 1V ;
  current_unit : 1A ;

  operating_conditions       ("AB0.5v45c") {
    process : 1 ;
    temperature : 45 ;
    voltage : 0.5 ;
  }
  default_operating_conditions : "AB0.5v45c" ;

  input_voltage(default) {
    vi : 0 ;
    vh : 0.5 ;
    vim : 0 ;
    vin : 0.5 ;
  }

}
[download]

Hope this helps, BR.

Seeking for Perl wisdom...on the process of learning...not there...yet!

In reply to Re: How to add a new line after three or four lines from a pattern after getting that pattern by thanos1983
in thread How to add a new line after three or four lines from a pattern after getting that pattern by anirbanphys

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