pdeshpan has asked for the wisdom of the Perl Monks concerning the following question:

Hello! I have a statement in my code as follows:

print "\na:$wrds[11]\t b:$wrds[12]\t c:$wrds[13]\t d:$wrds[14]\t e:$wrds[15]";

It's corresponding output I saw was as follows:

         d:      e:0x4024d018    c:

Now, I want to understand where did a:, b: go? and why was the order d:, e: and c: instead of natural English alphabet order?

Replies are listed 'Best First'.
Re: understanding print
by FunkyMonk (Bishop) on Aug 11, 2008 at 14:05 UTC
    Does $words[13] contain chr 13 (carriage return)?

    Update:

    use Data::Dumper;
$Data::Dumper::Useqq = 1;
print Dumper $words[13];

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    I think you'll see "\r" in there somewhere.

    Update^2: s/say/print/;

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      Hello FunkyMonk! Thanks for replying. Incidently my code  wrds[13] is what had contained the information that I needed. The code was working with information from  wrds[13]. Unfortunately I could not try Data::Dump but the coincidence of you suspecting something about  wrds[13] and it containing my info. is strange. I used a work around (of manually putting the string in my variable which is not what I had written the code for) and went ahead with my work. But I shall be thankful if order change is understood. Regards.
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        What FunkyMonk was getting to is that printing a carriage return ("\r") causes the cursor to move to the first column on many terminals. We suspect the value of $wrds[13] contains that character. 

        >perl -le"print qq{abcdef\rghi}"
ghidef

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        Unfortunately I could not try Data::Dump

        Why not?

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Re: understanding print
by Anonymous Monk on Aug 11, 2008 at 14:35 UTC
    Terminals are tricky 
    C:\> hexdump 2echo >2

C:\> hexdump 2
00000000: 45 43 48 4F 20 69 73 20 - 6F 6E 2E 0D 0A          |ECHO is o
+n.  |
0000000d;

C:\> od 2
0000000 041505 047510 064440 020163 067157 006456 000012
0000015

C:\> od -tc 2
0000000   E   C   H   O       i   s       o   n   .  \r  \n
0000015

C:\> perl -e"print qq~$_\r~ for 1 .. 3"
3
C:\> perl -e"print qq~$_\r~ for 1 .. 3" >2

C:\> hexdump 2
00000000: 31 0D 32 0D 33 0D       -                         |1 2 3 |
00000006;

C:\> od 2
0000000 006461 006462 006463
0000006

C:\> od -tc 2
0000000   1  \r   2  \r   3  \r
0000006

C:\> od -ta 2
0000000   1  cr   2  cr   3  cr
0000006

C:\>od -abcx 2
0000000   1  cr   2  cr   3  cr
        061 015 062 015 063 015
          1  \r   2  \r   3  \r
        0d31 0d32 0d33
0000006

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Re: understanding print
by graff (Chancellor) on Sep 20, 2008 at 17:42 UTC
    I'm sure you have worked out at least one good solution by now, but FWIW, you could try doing this first, before the print statement: 
    for ( @wrds[11..15] ) { s/^\s+//; s/\s+$//; s/\s+/ /g }

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    That's one of those good habits to get into when handling unreliable input data and trying to format it for nice, coherent printing.
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