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### Re: Weird "soundex" algorithm

by broquaint (Abbot)
 on Aug 28, 2003 at 15:17 UTC ( #287405=note: print w/replies, xml ) Need Help??

in reply to Weird "soundex" algorithm

```sub weirdex {
local \$_ = shift;

tr/a-zA-Z//dc;
tr/a-zA-Z//s;
m/[aeiou]/g and substr(\$_, pos) =~ s/[aieuo]//g;

\$_;
}

print "\$_ - ", weirdex(\$_), \$/
for "giulienk", "larry wall", "etheroskedasticity";

__output__

giulienk - gilnk
larry wall - larywl
etheroskedasticity - ethrskdstcty
tr//, m// and s///, pos and substr are your friends :)
HTH

_________
broquaint

Replies are listed 'Best First'.
Re: Re: Weird "soundex" algorithm
by giulienk (Curate) on Aug 28, 2003 at 15:32 UTC
Thanks to yours and jmcnamara's reply: i totally forgot about the power of tr/// modifiers, especially c and s, which i never used before. :)

\$|=\$_="1g2i1u1l2i4e2n0k",map{print"\7",chop;select\$,,\$,,\$,,\$_/7}m{..}g

Re: Re: Weird "soundex" algorithm
by diotalevi (Canon) on Aug 28, 2003 at 19:10 UTC

Nice. I was unhappy with your vowel stripping though. You use a looping match for offsets into \$_ but really, you only have to find the *first* vowel and then no looping is required.

```#  m/[aeiou]/g and substr(\$_, pos) =~ s/[aieuo]//g;
/[aeiou]/ and substr( \$_, \$+[0] ) =~ tr/aeiou//d;
You use a looping match for offsets into \$_ but really ...
Er, what looping? The /g matches the first vowel then saves the position of the match for substr which the replace then operates on. I didn't want to use the \$+ variable because of the overhead it invokes.
HTH

_________
broquaint

Er... what overhead? You mean of making an array access because that's all it is. @+ and @- don't invoke the \$`, \$& and \$' penalties. Those arrays are just offsets into the string. \$-[0] is the offset of the beginning of the string and \$+[0] is the offset of the end of the string. Using those doesn't prompt perl to do all the copying that capturing, \$`, \$&, and \$' do. Its just not the same thing.

Granted, I did miss that scalar /g loops only once and in this usage that'd be the only loop ever used. I find myself avoiding pos() after learning that it doesn't survive a local() on the variable in question. That's just style though.

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