Comments on: Flattening Hashes In Python

By: mpdehaan

mpdehaan — Tue, 12 Apr 2011 11:42:16 +0000

With semicolons and nested ternaries, it’s not a one liner, it’s just bad code formatting

By: Anonymouse

Anonymouse — Fri, 05 Feb 2010 02:28:45 +0000

I was trying to view a verbose a hash, and I accidentally wrote that in a one-liner: ohai | ruby -ryaml -e "puts YAML::load(STDIN.read).each_pair{|k,v| puts k; v.respond_to?(:keys) ? v.keys.each {|z| puts ' ' + z.to_s + ' ' + v[z].inspect } : puts(' ' + v.to_s) }" | less -S

By: Klaus

Klaus — Wed, 06 Jan 2010 08:46:02 +0000

Hehe, we still should define a version for a Turing Machine, just for reference … Then the discussion, which language is the be best would be moot I wouldn’t want to start a religious war about it (not even about Emacs vs. vi, even though emacs is best )

BTW, the recursion is nice. I like recursion…

Klaus

By: Michael DeHaan

Michael DeHaan — Tue, 05 Jan 2010 23:42:16 +0000

I’m not really trying to say it was powerful or it wasn’t Nor was this about Perl at all. It’s just that I didn’t see an example of this on Google when I was looking for a Python version, so I’m sharing mine.

Besides, all the cool kids are using Erlang and Intercal.

By: rich

rich — Tue, 05 Jan 2010 22:31:30 +0000

Perl and Python are very similar languages in what you can express. The next level languages are things like Lisp. Above that, take a look at OCaml + camlp4, for a unique combination of powerful language and macros.

By: mpdehaan

mpdehaan — Tue, 05 Jan 2010 22:13:05 +0000

Of course. Mainly I wanted to share the shorter algorithm, and feed it to Google.

I’m sure it can be done in less code or more efficiently as well, which I haven’t really tried to do.

By: Klaus

Klaus — Tue, 05 Jan 2010 22:02:36 +0000

Hi,

the module may be a nice and general implementation, but your python implementation can be implemented 1:1 in perl, to be honest…

Just wanted to know:

sub flatten {
my ($ds, $result, $memo) = @_;

my %empty = ();
$result = \%empty if (!defined $result) ;

my @elt;
while (@elt = each %{$ds}) {
if ($memo eq “”) {
$new_memo = $elt[0];
} else {
$new_memo = “$memo.$elt[0]“;
}
if (ref $elt[1] eq “HASH”) {
$result = flatten($elt[1], $result, $memo=$new_memo);
} else {
$result->{$new_memo} = $elt[1];
}
}
$result;
}

Klaus