There's a difference between $count++ and ++$count.

The first one increments it after using it (ie. prints its value first, and then adds one). The second increments it before using it.

Try using ++$count instead, and you should see the answer you expect.

Look at the first example in "Auto-increment and Auto-decrement" here.

So your immediate problem would be solved by preincrementing instead of postincrementing, so that the incrementing happens before you print.

But your code could be simplified further by using $., documented in perlvar.

while( <FH> ) {
  print "$.:$_";
}
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It starts at zero, so if you need it to start counting at some other base you'll have to add.

  print $. + 1, ":$_";
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It starts at zero…

Actually, it starts at 1, not 0.

C:\strawberry>perl -nE "say $." README.txt | head
1
2
3
4
5
6
7
8
9
10

C:\strawberry>
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It's probably also worth demonstrating here the usual idiom for resetting the line number to 1 for each file in @ARGV when using <>.

# @ARGV may have more than one file in it

while (<ARGV>) {
    print "$.:$_\n";
}
continue {
    close ARGV if eof;
}
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*head-bonk*

Ever since the alien abduction I've had a hard time remembering that $. is 1-based. ;)




Dave

It starts at zero...

Quoth perlvar (emphases added): Each filehandle in Perl counts the number of lines that have been read from it. ... When a line is read from a filehandle (via "readline()" or "<>") ... $. becomes an alias to the line counter for that filehandle.

So I would say davido's assertion is not without justification:  $. starts out undefined (which is very like zero) and happily becomes 1 by aliasing when the first line is read. I assume the internal filehandle line counter is 0 or undefined prior to any read on the handle. So there.

>perl -wMstrict -le
"my $filename = 'text';
 open my $fh, '<', $filename or die qq{opening '$filename': $!};
 ;;
 print qq{\$. initially: }, defined $. ? qq{'$.'} : 'undefined';
 ;;
 while (<$fh>) {
   chomp;
   print qq{$.: '$_'};
   }
 ;;
 close $fh or die qq{closing '$filename': $!};
"
$. initially: undefined
1: 'now is the time'
2: 'foo bar baz'
3: 'how now brown cow'
4: 'four score and seven'
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Hi vyeddula,
I initialized count to 1
Yes you did.

there is $count++ which it has to make it start from 2

No, with print $count++; you are saying, print the present value of $count, then increase it value by 1.

So if you want the value to start from 2, then increase the value first then print like so: print ++$count it is called pre-incremental.

Test this:

my $count = 1;
while(<DATA>)
{
             print ++$count;
             print ":$_";
}

__DATA__
apple
snake
cow
dog
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You have been given three good answers, but I especially support Davido's recommendation to use the "$." variable (line count in the file being read) rather than counting yourself the line number. It is simpler, easier and probably faster.

We could be expected to do that pretty much automatically if you took the trouble to format your nodes as recommended by the directions at the text-input box where you created this.

Use code tags ( <c>...</c> ) around data, as well as around code.