Comments on: Hash Transforms in Ruby

By: avdi

avdi — Fri, 20 Nov 2009 13:34:23 +0000

Yeah, the whole “returning an Array of Arrays” business is a weird wart and IMO violates the POLS.

By: avdi

avdi — Fri, 20 Nov 2009 13:34:23 +0000

Yeah, the whole “returning an Array of Arrays” business is a weird wart and IMO violates the POLS.

By: llimllib

llimllib — Fri, 20 Nov 2009 13:28:18 +0000

When I was transitioning to Ruby from Python et al, the difficulty of doing this was remarkable to me. In python, it's just:

In [1]: x = {1:2, 3:4, 5:6, 7:8, 9:0}

In [2]: dict((str(k), v) for k,v in x.iteritems())

Out[2]: {'1': 2, '3': 4, '5': 6, '7': 8, '9': 0}

So the equivalent function, adding the "deep" option, would be:

def dict_transform(a_dict, f, deep=False):
return dict(f(k,v) if not deep or not isinstance(v, dict) else f(k, dict_transform(v, f, deep))
for k,v in a_dict.iteritems())

By: avdi

avdi — Fri, 20 Nov 2009 13:18:20 +0000

Part of the impetus for writing mine was I tend to get the Hash[*...] bit wrong… e.g. I'll leave out the splat.

By: jjulian

jjulian — Fri, 20 Nov 2009 13:14:07 +0000

Funny, I just googled and wrote a one-liner last night to transform keys AND values to strings.

Hash[*h.map {|k,v| [k.to_s,v.to_s] }.flatten]

Not as robust as your examples, but a quick way since I know my input is flat.