Re: Removing leading whitespace and removing alternate newlines
On Oct 31, 10:01 am, brian5432...@yahoo.co.uk (Brian) wrote: Hi guys, long time no working with PERL :-) I have just installed 5.2.12 First, I am trying to remove leading tabs spaces but the following leaves a few blanks at the beginning of each line, could someone be kind enough to point out the error of my ways please? :-) #!/usr/bin/perl local $/=undef; open(FILE, smith3.txt) || die (Error\n); $string = FILE; $string =~ s/\s//; #remove leading spaces print $string; Secondly, I would like to remove newline from alternate lines, ie I would like to remove from lines 1,3,5,7 etc. What would be the simplest way of getting even line numbers to print on the same line as odds? Thanks muchly Brian Is $/ a special variable of some kind? -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: Removing leading whitespace and removing alternate newlines
yeah, it's one of those that you shouldn't modify or you might start seeing unexpected results. read perlvar or google 'perl input record separator' for more. On Mon, Nov 1, 2010 at 10:14 AM, Matthew Young mab...@gmail.com wrote: On Oct 31, 10:01 am, brian5432...@yahoo.co.uk (Brian) wrote: Hi guys, long time no working with PERL :-) I have just installed 5.2.12 First, I am trying to remove leading tabs spaces but the following leaves a few blanks at the beginning of each line, could someone be kind enough to point out the error of my ways please? :-) #!/usr/bin/perl local $/=undef; open(FILE, smith3.txt) || die (Error\n); $string = FILE; $string =~ s/\s//; #remove leading spaces print $string; Secondly, I would like to remove newline from alternate lines, ie I would like to remove from lines 1,3,5,7 etc. What would be the simplest way of getting even line numbers to print on the same line as odds? Thanks muchly Brian Is $/ a special variable of some kind? -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: Removing leading whitespace and removing alternate newlines
$string =~ s/^\s+//; http://oreilly.com/catalog/9781565922433/ page 43 That book is my bible!!! On Sun, Oct 31, 2010 at 11:01 AM, Brian brian5432...@yahoo.co.uk wrote: Hi guys, long time no working with PERL :-) I have just installed 5.2.12 First, I am trying to remove leading tabs spaces but the following leaves a few blanks at the beginning of each line, could someone be kind enough to point out the error of my ways please? :-) #!/usr/bin/perl local $/=undef; open(FILE, smith3.txt) || die (Error\n); $string = FILE; $string =~ s/\s//; #remove leading spaces print $string; Secondly, I would like to remove newline from alternate lines, ie I would like to remove from lines 1,3,5,7 etc. What would be the simplest way of getting even line numbers to print on the same line as odds? Thanks muchly Brian -- Richard Hug 813-973-3783 cell 813-361-7946
Re: Removing leading whitespace and removing alternate newlines
On Sunday 31 October 2010 17:01:24 Brian wrote:
Hi guys, long time no working with PERL :-)
See:
http://perl.org.il/misc.html#pl_vs_pl
I have just installed 5.2.12
You probably mean perl-5.12.2 .
A few more comments on your code:
First, I am trying to remove leading tabs spaces but the following leaves
a few blanks at the beginning of each line, could someone be kind enough
to point out the error of my ways please? :-)
#!/usr/bin/perl
Add strict and warnings. See:
http://perl-begin.org/tutorials/bad-elements/
local $/=undef;
You probably don't want to read the entire file to memory at once, as it may
be very large.
open(FILE, smith3.txt) || die (Error\n);
Use three-args-open, lexical filehandles, and use a more descriptive error
than Error..
$string = FILE;
$string =~ s/\s//; #remove leading spaces
This will remove only the first whitespace character (and in your case, from
the entire file).
print $string;
Secondly, I would like to remove newline from alternate lines, ie I would
like to remove from lines 1,3,5,7 etc.
What would be the simplest way of getting even line numbers to print on the
same line as odds?
Use something like this (untested):
[code]
#!/usr/bin/perl
use strict;
use warnings;
my $filename = shift(@ARGV)
or die No filename specified in command-line;
open my $fh, , $filename
or die Cannot open '$filename' for reading - $!;
my $line_num = 1;
while (my $line = $fh)
{
chomp ($line);
$line =~ s{\A\s+}{};
print $line;
if ($line_num % 2 == 0)
{
print \n;
}
}
continue
{
$line_num++;
}
close($fh);
[/code]
Regards,
Shlomi Fish
Thanks muchly
Brian
--
-
Shlomi Fish http://www.shlomifish.org/
Best Introductory Programming Language - http://shlom.in/intro-lang
rindolf She's a hot chick. But she smokes.
go|dfish She can smoke as long as she's smokin'.
Please reply to list if it's a mailing list post - http://shlom.in/reply .
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For additional commands, e-mail: beginners-h...@perl.org
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Re: Removing leading whitespace and removing alternate newlines
Thank you Shlomi, I'll test part 2 tomorrow when I have more time.
As for part one, what would be the better way of writing the code so that I can
read/treat one line at a time?
thanks again
Brian
From: Shlomi Fish shlo...@iglu.org.il
To: beginners@perl.org
Cc: Brian brian5432...@yahoo.co.uk
Sent: Sun, October 31, 2010 4:23:52 PM
Subject: Re: Removing leading whitespace and removing alternate newlines
On Sunday 31 October 2010 17:01:24 Brian wrote:
Hi guys, long time no working with PERL :-)
I have just installed 5.2.12
You probably mean perl-5.12.2 .
A few more comments on your code:
First, I am trying to remove leading tabs spaces but the following leaves
a few blanks at the beginning of each line, could someone be kind enough
to point out the error of my ways please? :-)
#!/usr/bin/perl
local $/=undef;
You probably don't want to read the entire file to memory at once, as it may
be very large.
open(FILE, smith3.txt) || die (Error\n);
Use three-args-open, lexical filehandles, and use a more descriptive error
than Error..
$string = FILE;
$string =~ s/\s//; #remove leading spaces
This will remove only the first whitespace character (and in your case, from
the entire file).
print $string;
Secondly, I would like to remove newline from alternate lines, ie I would
like to remove from lines 1,3,5,7 etc.
What would be the simplest way of getting even line numbers to print on the
same line as odds?
Use something like this (untested):
[code]
#!/usr/bin/perl
use strict;
use warnings;
my $filename = shift(@ARGV)
or die No filename specified in command-line;
open my $fh, , $filename
or die Cannot open '$filename' for reading - $!;
my $line_num = 1;
while (my $line = $fh)
{
chomp ($line);
$line =~ s{\A\s+}{};
print $line;
if ($line_num % 2 == 0)
{
print \n;
}
}
continue
{
$line_num++;
}
close($fh);
[/code]
Regards,
Shlomi Fish
Thanks muchly
Brian
--
Re: Removing leading whitespace and removing alternate newlines
Thanks Shlomi, your untested code worked first time.
:-)
From: Shlomi Fish shlo...@iglu.org.il
To: beginners@perl.org
Cc: Brian brian5432...@yahoo.co.uk
Sent: Sun, October 31, 2010 4:23:52 PM
Subject: Re: Removing leading whitespace and removing alternate newlines
On Sunday 31 October 2010 17:01:24 Brian wrote:
Hi guys, long time no working with PERL :-)
Secondly, I would like to remove newline from alternate lines, ie I would
like to remove from lines 1,3,5,7 etc.
What would be the simplest way of getting even line numbers to print on the
same line as odds?
Use something like this (untested):
[code]
#!/usr/bin/perl
use strict;
use warnings;
my $filename = shift(@ARGV)
or die No filename specified in command-line;
open my $fh, , $filename
or die Cannot open '$filename' for reading - $!;
my $line_num = 1;
while (my $line = $fh)
{
chomp ($line);
$line =~ s{\A\s+}{};
print $line;
if ($line_num % 2 == 0)
{
print \n;
}
}
continue
{
$line_num++;
}
close($fh);
[/code]
Regards,
Shlomi Fish
Thanks muchly
Brian
--
To unsubscribe, e-mail: beginners-unsubscr...@perl.org
For additional commands, e-mail: beginners-h...@perl.org
http://learn.perl.org/
Re: Removing leading whitespace and removing alternate newlines
Brian wrote: Hi guys, long time no working with PERL :-) Hello, I have just installed 5.2.12 First, I am trying to remove leading tabs spaces Just tabs and spaces? Your code says all whitespace. but the following leaves a few blanks at the beginning of each line, You code only removes one whitespace character. could someone be kind enough to point out the error of my ways please? :-) #!/usr/bin/perl use warnings; use strict; local $/=undef; Or just: local $/; open(FILE, smith3.txt) || die (Error\n); Better as: open FILE, '', 'smith3.txt' or die Cannot open 'smith3.txt' $!; $string =FILE; my $string = FILE; $string =~ s/\s//; #remove leading spaces $string =~ s/^[ \t]+//mg; #remove leading spaces and tabs from every line print $string; No need to stringify something that is alraedy a string: print $string; perldoc -q quoting Secondly, I would like to remove newline from alternate lines, ie I would like to remove from lines 1,3,5,7 etc. What would be the simplest way of getting even line numbers to print on the same line as odds? my $count; $string =~ s/(\n)/ $count++ % 2 ? $1 : '' /eg; John -- Any intelligent fool can make things bigger and more complex... It takes a touch of genius - and a lot of courage to move in the opposite direction. -- Albert Einstein -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
Re: Removing leading whitespace and removing alternate newlines
Thank you John From: John W. Krahn jwkr...@shaw.ca To: Perl Beginners beginners@perl.org Sent: Sun, October 31, 2010 8:59:43 PM Subject: Re: Removing leading whitespace and removing alternate newlines Brian wrote: Hi guys, long time no working with PERL :-) Hello, I have just installed 5.2.12 First, I am trying to remove leading tabs spaces Just tabs and spaces? Your code says all whitespace. but the following leaves a few blanks at the beginning of each line, You code only removes one whitespace character. could someone be kind enough to point out the error of my ways please? :-) #!/usr/bin/perl use warnings; use strict; local $/=undef; Or just: local $/; open(FILE, smith3.txt) || die (Error\n); Better as: open FILE, '', 'smith3.txt' or die Cannot open 'smith3.txt' $!; $string =FILE; my $string = FILE; $string =~ s/\s//; #remove leading spaces $string =~ s/^[ \t]+//mg; #remove leading spaces and tabs from every line print $string; No need to stringify something that is alraedy a string: print $string; perldoc -q quoting Secondly, I would like to remove newline from alternate lines, ie I would like to remove from lines 1,3,5,7 etc. What would be the simplest way of getting even line numbers to print on the same line as odds? my $count; $string =~ s/(\n)/ $count++ % 2 ? $1 : '' /eg; John -- Any intelligent fool can make things bigger and more complex... It takes a touch of genius - and a lot of courage to move in the opposite direction. -- Albert Einstein -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
