(jeffa) Re: Vanishing Data

Grasshopper needs meditation first:

#!/usr/local/bin/perl -l

use strict;

foreach (0,'',undef) {
   print "'$_' is zero number" if $_ == 0;
   print "'$_' is zero string" if $_ eq '0';
   print "'$_' is empty string" if $_ =~ /^$/;
   print "'$_' is empty string" if $_ eq '';
   print "'$_' is undef" if ! defined $_;
}
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jeffa

L-LL-L--L-LL-L--L-LL-L--
-R--R-RR-R--R-RR-R--R-RR
B--B--B--B--B--B--B--B--
H---H---H---H---H---H---
(the triplet paradiddle with high-hat)

Comment on (jeffa) Re: Vanishing Data Download Code

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Re: (jeffa) Re: Vanishing Data by thelenm (Vicar) on May 02, 2002 at 16:31 UTC
It's a really minor point, but this statement is not strictly true: `print "'$_' is empty string" if $_ =~ /^$/;` [download] What you want is `/^\z/`, since `/^$/` will also match a single newline, as evidenced by the following test: `print "Empty matches ^\$ --> ", ("" =~ /^$/ ? 'yes' : 'no'), "\n"; print "Newline matches ^\$ --> ", ("\n" =~ /^$/ ? 'yes' : 'no'), "\n" +; print "Empty matches ^\\z --> ", ("" =~ /^\z/ ? 'yes' : 'no'), "\n"; print "Newline matches ^\\z --> ", ("\n" =~ /^\z/ ? 'yes' : 'no'), "\n +";` [download]	[reply] [d/l] [select]

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Re: (jeffa) Re: Vanishing Data
by thelenm (Vicar) on May 02, 2002 at 16:31 UTC

  print "'$_' is empty string" if $_ =~ /^$/;
[download]

/^\z/

/^$/

print "Empty   matches ^\$  --> ", ("" =~ /^$/ ? 'yes' : 'no'), "\n";
print "Newline matches ^\$  --> ", ("\n" =~ /^$/ ? 'yes' : 'no'), "\n"
+;
print "Empty   matches ^\\z --> ", ("" =~ /^\z/ ? 'yes' : 'no'), "\n";
print "Newline matches ^\\z --> ", ("\n" =~ /^\z/ ? 'yes' : 'no'), "\n
+";
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