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

I hope someone can help me here, I need to compare the month entered by the user I.E. as a date say 08 for the month of august but I ran into a snag between 07 and 08 I can only get it to work as an 8 but I need it as 08 for file naming. if I use 08 I get an error for illegal octal but I dont on say 07 for July. I've tried ==, eq, '08' "08" and about everything else but I'm still stuck. Is this a bug? or can I get some help? thanks.... still learning 
if ($month eq 07 || 7) { 
    $monthStamp = "July";
        print "$monthStamp";
}
if ($month eq 08 || 8) {
    $monthStamp = "August";
        print "$monthStamp";
}

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Replies are listed 'Best First'.
Re: problem or bug?
by Masem (Monsignor) on Oct 11, 2001 at 23:03 UTC
    You probably want: 
    if ( $month eq '07' || $month eq '7' ) { ... }

    [download]
    While it would seem to be intuitive, perl cannot use a single ==/eq to compare many things at once, you have to do each separately.

    -----------------------------------------------------
    Dr. Michael K. Neylon - mneylon-pm@masemware.com || "You've left the lens cap of your mind on again, Pinky" - The Brain
    It's not what you know, but knowing how to find it if you don't know that's important

[reply]
[d/l]
Re: problem or bug?
by dragonchild (Archbishop) on Oct 11, 2001 at 23:04 UTC 
    if ($month + 0 == 7) {
...

# Or, better would be ...
@month_names = (
'',
'January',
...
);

$monthStamp = $month_names[$month];

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    ------
    We are the carpenters and bricklayers of the Information Age.

    Don't go borrowing trouble. For programmers, this means Worry only about what you need to implement.

[reply]
[d/l]
      I think the '+ 0' trick to force a numeric value is unnecessary here. It looks like '==' already does that for you. (of course your second suggestion is better than either of these, but still...) 
      #!/usr/bin/perl -wT
use strict;

my @vals = ('07','7',07,7,8);

# eq tests
for my $month (@vals) {
  print $month, $month eq 7 ? ' eq' : ' !eq', " 7\n";
}
print "\n";

# == tests
for my $month (@vals) {
  print $month, $month == 7 ? ' ==' : ' !==', " 7\n";
}
print "\n";

=OUTPUT
07 !eq 7
 7  eq 7
 7  eq 7
 7  eq 7
 8 !eq 7

07  == 7
 7  == 7
 7  == 7
 7  == 7
 8 !== 7

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      -Blake

[reply]
[d/l]
      Thanks guys!! learn something new everyday! :)
[reply]
Re: problem or bug?
by guidomortonski (Sexton) on Oct 12, 2001 at 02:52 UTC
    You're trying to evaluate $month as a string. Try 

    if ($month == 7) { 
    $monthStamp = "July";
    print "$monthStamp";
}

    [download]

    This should work regardless of whether $month contains a number 7 or a string "07".

    Guy

[reply]
[d/l]

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