Re: Re^2: A classic use of prototypes: map2

You get trouble with undefined quantities if you go beyond the minimum last index. Your updated code still uses @$arrayref instead of $#$arrayref as the last index of the referenced array.

After Compline,
Zaxo

Comment on Re: Re^2: A classic use of prototypes: map2

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Re^4: A classic use of prototypes: map2 (<) by tye (Sage) on May 02, 2004 at 15:27 UTC
Since < is used, @$aref is correct. Using $#$aref would work if <= were used. I prefer the former. But for that case the variable shouldn't be called "last index" and in the current code (that appears to keep changing -- so I'm not claiming you were mistaken) it isn't ($rv_len). FYI, Algorithm::Loops includes several flavors of 'mapcar' which are like map2 but take N lists and pass the items into the code block via @_. The module documentation also discusses why I chose to use prototypes despite usually avoiding them. - tye	[reply]

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Re^4: A classic use of prototypes: map2 (<)
by tye (Sage) on May 02, 2004 at 15:27 UTC

Since < is used, @$aref is correct. Using $#$aref would work if <= were used. I prefer the former. But for that case the variable shouldn't be called "last index" and in the current code (that appears to keep changing -- so I'm not claiming you were mistaken) it isn't ($rv_len).

FYI, Algorithm::Loops includes several flavors of 'mapcar' which are like map2 but take N lists and pass the items into the code block via @_. The module documentation also discusses why I chose to use prototypes despite usually avoiding them.

- tye

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