Re: Hash table

[moritz]

Do hashtables in Perl always have keys?

An empty hash doesn't have any keys, but it's not the most useful case.

I am asked to create a hashtable from a database.But there is no unique values so that cant make any column as key.

I guess you haven't been asked to make a hash table just for the fun of it, but because somebody needs it. That somebody can tell you what the keys should be.

Note that even if there is no unique column in your database, there might a comination of columns that is unique, which you could then use as keys for the hash table (for example delimited by the zero-byte "\x0").

Or the user of the hash table might expect multiple values to be grouped as an array, or simply the first or last of the values.

A lil confused after hearing this requirement.

Then asked for clarification. But don't ask us, ask the one who made the requirements.

[james2vegas]

or automatically delimited with \034 by using multi-dimensional array emulation:

$hash{$key1,$key2,$key3}

[Jim]

Ah, AWK!