Re^2: problems dereferencing an array of arrays as a hash value

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Re^3: problems dereferencing an array of arrays as a hash value by gmargo (Hermit) on Nov 23, 2009 at 17:42 UTC
The brackets `[]` create a reference to an anonymous array. With an array inside the brackets like `[ @pktClassList ]`, the contents of the `@pktClassList` array are copied into the new anonymous array. There is a different way to get the same effect, but which avoids the second copy. If the `@pktClassList` array is a local variable in a subroutine, which gets used only once before going out of scope, then you could have used the `@pktClassList` array directly like this: `case /packetclassifierlist/ { $tlvHash{pktClassList} = \@pktClassLi +st }` [download] The key is the scope of the original `@pktClassList` array - when the variable goes out of scope, it becomes an anonymous array by virtue of being referenced by the `%tlvHash` hash. Quite unlike the C language. See perlref for more info on references. Anonymous arrays are addressed early in the document.	[reply] [d/l] [select]

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Re^3: problems dereferencing an array of arrays as a hash value
by gmargo (Hermit) on Nov 23, 2009 at 17:42 UTC

The brackets [] create a reference to an anonymous array. With an array inside the brackets like [ @pktClassList ], the contents of the @pktClassList array are copied into the new anonymous array.

There is a different way to get the same effect, but which avoids the second copy. If the @pktClassList array is a local variable in a subroutine, which gets used only once before going out of scope, then you could have used the @pktClassList array directly like this:

case /packetclassifierlist/    { $tlvHash{pktClassList} = \@pktClassLi
+st }
[download]

The key is the scope of the original @pktClassList array - when the variable goes out of scope, it becomes an anonymous array by virtue of being referenced by the %tlvHash hash. Quite unlike the C language.

See perlref for more info on references. Anonymous arrays are addressed early in the document.

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