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From: jidanni on 11 Aug 2010 12:54
I don't think this is returning the empty string ("") actually:

$ man perlop
s/PATTERN/REPLACEMENT/msixpogce
Searches a string for a pattern, and if found, replaces that pattern with the replacement
text and returns the number of substitutions made. Otherwise it returns false (specifically,
the empty string).
$ echo iiii|perl -nwle 'print 1 + s/i//g'
5
$ echo iiii|perl -nwle 'print 1 + s/j//g'
1
$ echo iiii|perl -nwle 'print 1 + ""' #if it really were the empty string, this would happen:
Argument "" isn't numeric in addition (+) at -e line 1, <> line 1.
1

So maybe the man page should be reworded to say just what in fact is
going on.
From: Uri Guttman on 11 Aug 2010 14:11
>>>>> "j" == jidanni <jidanni(a)jidanni.org> writes:

j> I don't think this is returning the empty string ("") actually:
j> $ man perlop
j> s/PATTERN/REPLACEMENT/msixpogce
j> Searches a string for a pattern, and if found, replaces that pattern with the replacement
j> text and returns the number of substitutions made. Otherwise it returns false (specifically,
j> the empty string).
j> $ echo iiii|perl -nwle 'print 1 + s/i//g'

why all the work with echo and -n?

perl -wle 'print 1 + "iii" =~ /i/'
2

shows the same issues without all the extra cruft

it is returning the double valued false that other booleans also
return. it is both the empty string AND 0 and you can see that with
various inspection subs like ones in Scalar::Util. so you can use a
boolean result in numeric or string expressions and never get a
warning. it probably says null string because explaining that it really
is both is very wordy and would have to be explained everywhere a
boolean is returned. not enough of a big deal to worry about.

uri

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