> Again, there is no "TRUE list" of hash keys. To generate keys %hash, Perl has to traverse the entire internal hash table and return a list of the results to you. But again, Perl does this very, very quickly.

Sorry, but from my understanding this is incorrect.

There is a Linked List with keys and values in a fixed randomized order which is used by iterators like each , as well as keys and values

There is also a C-Array of "Buckets" for quick look up via hash-function, and these "Buckets" also point to a Linked List with all entries having the same hash-value aka "Collisions".

But this array is not traversed to generate the output for keys

UPDATE

Sorry ... looks like I had an incorrect or outdated source

according to https://www.cpan.org/authors/id/G/GA/GAAS/illguts-0.09.pdf

* RITER, EITER: 

 The first two fields are used to implement a single iterator over the
+ elements in the hash.
 RITER which is an integer index into the array referenced by ARRAY an
+d EITER which is a 
 pointer to an HE. In order find the next hash element one would first
+ look at EITER->next
 and if it turns out to be NULL, RITER is incremented until ARRAY[RITE
+R] is non-NULL. The
 iterator starts out with RITER = -1 and EITER = NULL.

[download]

and I'm not sure if this is still up to date, since new security requirements led to more randomization

Cheers Rolf
(addicted to the Perl Programming Language :)
Wikisyntax for the Monastery

In reply to Re^2: can I change hash keys or values directly (UPDATED) by LanX
in thread can I change hash keys or values directly by misterperl

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