I think your more succinct version will have a problem with the first key. This is because $_ going into the map is going to be 0 thus prev => $keys[0 - 1] will result in prev => 10. At the other end, I think that next => $keys[$#keys + 1] will do the right thing as pointing off the end of the array should result in undef.

Cheers,

JohnGG

In reply to Re^2: how to check which index $x is in an hash by johngg
in thread how to check which index $x is in an hash by Anonymous Monk

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