auto-vivification

There are simpler hacks around that auto-initialize a hash, but they suffer from auto-vivification of hash keys (ie.

Because it's very forgiving when prototyping a solution quickly, has great data-structures without a lot of setup (auto-vivification!), built in grep and map features, etc.

The big chunk of it was written in awk -- even though many awk scripts are one-liners, they don't have to be -- and that chunk was kinda impressive, making some clever use of associative arrays, auto-vivification, and more pretty advanced awk stuff.

I find I use it most in multi-level data structures, not unlike Perl's auto-vivification system: logins = {} for user, date in getLogins(): logins.setdefault(user, []).append(date) Here you login ends up having one key per "user" with a list of "date".

I find I use it most in multi-level data structures, not unlike Perl's auto-vivification system: logins = {} for user, date in getLogins(): logins.setdefault(user, []).append(date) Here you login ends up having one key per "user" with a list of "date".