Thanks to everyone for their input!
So I've tried out many of the methods, first making sure that each
works as I intended it.
Which is, I'm not concerned with multi-line text, just single line
data. That said, I have noted
that I should use \A and \z in general over ^ and $.
I wrote a 176 byte string for testing, and ran each method 1,000,000
times to time
the speed. The winner is: 3 regexp, using tr for intra-string
spaces. I found I could
make this even faster using a pointer to the variable versus passing
in the variable
as a local input parameter, modifying, then returning it. (In all
cases, my goal is
to write a sub for general use anywhere I want it, so I wrote each
possibility as
a sub. There ARE cases where I need to compare the the original
string with the
"cleaned" string, but I can deal with that as need be with local
variables.)
1ST PLACE - THE WINNER: 5.0s average on 5 runs
# Limitation - pointer
sub fixsp5 {
${$_[0]}=~tr/ \t\n\r\f/ /s;
${$_[0]}=~s/\A //;
${$_[0]}=~s/ \z//;
}
2nd PLACE - same as above, but with local variables - 6.0s average on
5 runs
sub fixsp4 {
my ($x)=...@_;
$x=~tr/ \t\n\r\f/ /s;
$x=~s/\A //;
$x=~s/ \z//;
return $x;
}
[ QUESTION - any difference using my $x=shift; ??? ]
3rd PLACE - 3 way tie, my method, either as variable in, change in
place, or pointer - 17.0s average
sub fixsp0 {
my ($x)=...@_;
$x=~s/^\s+//;
$x=~s/\s+$//;
$x=~s/\s+/ /g;
return $x;
}
# Limitation: pointer
sub fixsp1 {
${$_[0]}=~s/^\s+//;
${$_[0]}=~s/\s+$//;
${$_[0]}=~s/\s+/ /g;
}
# Limitation: change in place
sub fixsp2 {
$_[0]=~s/^\s+//;
$_[0]=~s/\s+$//;
$_[0]=~s/\s+/ /g;
}
4TH PLACE - 20.0s average on 5 runs (did not try change in place or as
pointer)
sub fixsp6 {
my ($x)=...@_;
s/\s+\z//, s/\A\s+//, s/\s+/ /g, for $x;
return $x;
}
5TH PLACE - DEAD LAST! (or DFL in some parlance) - 62.0s average on 3
runs
sub fixsp3 {
my ($x)=...@_;
$x=~s/^(\s+)|(\s+)$//g;
$x=~s/\s+/ /g;
return $x;
}
Any and all comments welcome.
David
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