Feature #14371
closedNew option "recursive: true" for Hash#transform_keys!
Description
Hash#transform_keys!
is available when we want to symbolize hash keys.
But in some/many cases (for example, receiver hash object is nested configuration tree loaded from any files), hash object are
nested object, which has hashes or arrays of hashes as values.
It's super useful if we can transform keys of such nested values.
My proposal is Hash#transform_keys!(recursive: true, &:to_sym)
. Pseudo code is:
def transform_keys!(recursive: false, &block)
# do original transform_keys! here
values.each do |v|
if v.respond_to?(:each)
v.each{|i| i.transform_keys!(recursive: true, &block) if i.respond_to?(:transform_keys!) }
else v.respond_to?(:transform_keys!)
v.transform_keys!(recursive: true, &block)
end
end if recursive
end
The most major usage example is: config = MyAwesomeFormat.load(file); config.transform_keys!(recursive: true, &:to_sym)
.
Updated by nobu (Nobuyoshi Nakada) almost 7 years ago
- Description updated (diff)
tagomoris (Satoshi TAGOMORI) wrote:
if v.respond_to?(:each) else v.respond_to?(:transform_keys!)
Why prefer each
over transform_keys!
?
And probably you wanted to write elsif
.
Updated by tagomoris (Satoshi Tagomori) almost 7 years ago
Why prefer
each
overtransform_keys!
?
And probably you wanted to writeelsif
.
Your points are correct. The ideal pseudo code is here:
def transform_keys!(recursive: false, &block)
# do original transform_keys! here
values.each do |v|
if v.respond_to?(:transform_keys!)
v.transform_keys!(recursive: true, &block)
elsif v.respond_to?(:each)
v.each{|i| i.transform_keys!(recursive: true, &block) if i.respond_to?(:transform_keys!) }
end
end if recursive
end
Updated by shevegen (Robert A. Heiler) almost 7 years ago
I agree with the proposal.
If it is approved, please do not forget meaningful documentation + perhaps
at the least one short example for using it (I refer to the recursive: true
option; http://ruby-doc.org/core-2.5.0/Hash.html#method-i-transform_keys-21).
Updated by matz (Yukihiro Matsumoto) almost 7 years ago
I don't think this proposal is a good idea for following reasons:
-
transform_keys
method to modify value part ofHash
-
recursive
option to change the behavior this much - it is much harder to implement
transform_keys(recursive:true)
(without bang)
I understand the intention behind the proposal. Probably you want to process JSON-like Array-Hash structures. I feel the recent demand to handle those data structures in Ruby. So we might need to add some utility methods in Ruby. I am not sure how yet. Maybe by adding methods to JSON module, or adding them both Array and Hash (like dig
).
Matz.
Updated by sakuro (Sakuro OZAWA) almost 7 years ago
FYI, ActiveSupport implemented these functionalities as separate methods:
Updated by tagomoris (Satoshi Tagomori) almost 7 years ago
- Status changed from Open to Rejected
I see. Thank you!