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

Hello monks,

just a question, is there anyway for me to combine below 2 statement into 1?
thank you in advance!!
($num) = $num =~ m#20(\d)#;
($num) = sprintf("%02d",$num);

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Re: anyway to combine these two steps?
by ikegami (Patriarch) on Jan 19, 2010 at 07:02 UTC

    You are assuming it always matches (or else you'd get a warning), so I'm going to rely on that same assumption. 

    ($num) = $num =~ /2(0\d)/;

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    Without the assumption: 

    $num = $num =~ /2(0\d)/ ? $1 : undef;

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    An alternate solution: 

    (...) = map sprintf('%02d', $_), ...

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Re: anyway to combine these two steps?
by moritz (Cardinal) on Jan 19, 2010 at 11:24 UTC 
    $num =~ s/.*?20(\d).*/0$1/gs

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    Since \d always matches one digit, the sprintf is not really needed.

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Re: anyway to combine these two steps?
by Anonymous Monk on Jan 19, 2010 at 06:59 UTC
    sprintf("%02d", $num =~ /20(\d)/);

    Note that $num =~ /20(\d)/ returns in list context the matches, and an empty list when there are none. So if you need to check whether a match occured, you can't do that here. However, you can provide to sprintf a default value, since it only uses the values it needs, and if there's an extra one it's ignored:

    sprintf("%02d", ($num =~ /20(\d)/), 0);

    A general example: print sprintf("%s\n", (/(bar)/), 'default') for qw(foo bar)

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      Another method, from the unnecessary ternary operator dept:

      $output = (/20(\d)/ ? sprintf("%02d", $1) : format_error("that isn't valid data!"));

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Re: anyway to combine these two steps?
by ambrus (Abbot) on Jan 19, 2010 at 11:17 UTC

    Actually you want $num = sprintf("%02d", $num % 100); to avoid Y2K errors.

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Re: anyway to combine these two steps?
by Anonymous Monk on Jan 19, 2010 at 06:44 UTC
    ($num) = $num =~ m#20(\d)#; ($num) = sprintf("%02d",$num);
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      ; separates statements. Putting two statements onto the same line does not make them a single statement any more than writing this as
      ($num)
 = 
$num
 =~ 
m#20(\d)#;
($num)
 = 
sprintf(
 "%02d",
 $num
);

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      makes it 11 statements.
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