in reply to unique filename

Hi lax

Have a look at Auto-increment and Auto-decrement

In particular: "The auto-increment operator has a little extra builtin magic to it."

Combined with neversaint's suggestion you may be able to dispense with the $i altogether.

As Dolly Parton famously said about looking at the docs: "That's what they're for!". Although she might not have been talking about the docs. :-)

Update

See my reply to Skeeve below.

Replies are listed 'Best First'.
Re^2: unique filename
by Skeeve (Parson) on Jul 21, 2006 at 08:13 UTC

    Hi wfsp!

    Can you please give an example how to get rid of the $i here? I always wanted that but never found a way to get filenames incremented without a temporary variable.

    perl -e '$fname= "testname_1";print "$fname\n",++$fname,"\n"'
    prints
    testane_1
    1
    Not a useable result...
    s$$([},&%#}/&/]+}%&{})*;#$&&s&&$^X.($'^"%]=\&(|?*{%
    +.+=%;.#_}\&"^"-+%*).}%:##%}={~=~:.")&e&&s""`$''`"e
[reply]
[d/l]
[select]

      The "magic" alphabetic increment doesn't work when there is a non (Update: ASCII it appears ) alphanumeric character in there such as the '_' in this case.

      /J\

[reply]
      Skeeve

      I should have tested before I posted :-)

      The 'magic' can be useful but with caveats. The following snippet shows when it does work (the first three) and when it doesn't (the final three).

      
#!/usr/bin/perl

use strict;
use warnings;

my @array = qw(a123 abc abc1 123a 123_1 abc_1);

for my $element (@array){
  print "before: $element\n";
  $element++;
  print "after: $element\n";
  print "\n";
}

__DATA__

output (with comments)

# these "do what you want"

before: a123
after: a124

before: abc
after: abd

before: abc1
after: abc2

# and these don't :-(

# if the string starts with a number
# Perl treats it as number

before: 123a
after: 124

# the _ always breaks the magic

before: 123_1
after: 124

# not at all sure what's happening here!

before: abc_1
after: 1

      [download]
[reply]
[d/l]

In Section Seekers of Perl Wisdom