You are creating hash elements with undef @a{@b}. This is called autovivication (see wikipedia for a nice explanation) and has nothing to do with the undef function. Something similar happens when you write @a{@b}= (1);. The hash would contain key a set to 1 and keys b and c set to undef

In reply to Re^3: Hash slice again by jethro
in thread Hash slice again by targetsmart

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