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Binary x repitition operator

kencl
User

Sep 2, 2001, 3:16 PM

Post #1 of 2 (292 views)

Binary x repitition operator	Can't Post

Just wondering if I can:

Code

shift (@ResultPointer) x 3;  # remove top 3 array rows

or would

Code

splice(@ResultPointer, 0, 3);

be more efficient?

Would there be a problem with either method if the array contained only 3 elements? IE would the result be the same as if I'd simply gone:

Code

@ResultPointer = ();  # only do this if there is exactly 3 elements!!!

>> If you can't control it, improve it, correlate it or disseminate it with PERL, it doesn't exist!

mhx
Enthusiast / Moderator

Sep 3, 2001, 11:11 AM

Post #2 of 2 (287 views)

Re: Binary x repitition operator [In reply to]	Can't Post

In Reply To

Just wondering if I can:

Code

shift (@ResultPointer) x 3;  # remove top 3 array rows

No. This would shift the first element off the array @ResultPointer, repeat it 3 times in string context and return a string that isn't used. Perl would yield

Code

Useless use of repeat (x) in void context

if run with -w.

In Reply To

or would

Code

splice(@ResultPointer, 0, 3);

be more efficient?

I think it's the most efficient way. Using three shifts wouldn't be as efficient. splice is about 40 percent faster in this case.

In Reply To

Would there be a problem with either method if the array contained only 3 elements?

No, except for the fact that the first method wouldn't work for the above reason.
Hope this helps.

-- Marcus

Code

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($">>=1)&1?-hex:hex)+0140)}/./g;$"=chr$";s;.;\u$&;for@_[0,2];print"@_,"

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