- reverse LIST
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In list context, returns a list value consisting of the elements of LIST in the
opposite order. In scalar context, concatenates the elements of LIST and returns a string
value with all characters in the opposite order.
print reverse <>; # line tac, last line first
undef $/; # for efficiency of <>
print scalar reverse <>; # character tac, last line tsrif
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This operator is also handy for inverting a hash, although there are some caveats. If a
value is duplicated in the original hash, only one of those can be represented as a key in
the inverted hash. Also, this has to unwind one hash and build a whole new one, which may
take some time on a large hash, such as from a DBM file.
%by_name = reverse %by_address; # Invert the hash
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