hash-of-hashes

问题 I was looking around for a clean way to do this and I found some workarounds but did not find anything like the slice (some people recommended to use a gem but I think is not needed for this operations, pls correct me if I am wrong), so I found myself with a hash that contains a bunch of hashes and I wanted a way to perform the Slice operation over this hash and get also the key/value pairs from nested hashes, so the question: Is there something like deep_slice in ruby? Example: input: a = {b

问题 I was looking around for a clean way to do this and I found some workarounds but did not find anything like the slice (some people recommended to use a gem but I think is not needed for this operations, pls correct me if I am wrong), so I found myself with a hash that contains a bunch of hashes and I wanted a way to perform the Slice operation over this hash and get also the key/value pairs from nested hashes, so the question: Is there something like deep_slice in ruby? Example: input: a = {b

问题 I have just picked up Perl. I have a little confusion with accessing hash values. Below is the code where I am trying to access the values of a hash inside a hash. Since am using a simple text editor to code, I am not able to figure out what can be the problem. Please help my %box = ( Milk => { A => 5, B => 10, C => 20, }, Chocolate => { AB => 10, BC => 25, CD => 40, }, ); foreach my $box_key(keys %box) { foreach my $inside_key (keys %box{box_key}) print "$box_key"."_$inside_key""is for

问题 Is there a way to create a hash of hashes in C++? Effectively I am trying to do what you can do in Perl but only in C++. Here is an example of Perl code I would like to have happen in C++ %hash = ( gameobject1 => { position => { x_loc => 43, y_loc => 59, } rect_size => { width => 5, height => 3, } collidable => 1, sounds => { attack => "player_attack.ogg", jump => "player_jump1.ogg", jump_random => [qw/player_jump1.ogg player_jump2.ogg player_jump3.ogg/] } }, gameobject2 => { position => { x

问题 This question already has answers here : Ruby Style: How to check whether a nested hash element exists (16 answers) How to avoid NoMethodError for nil elements when accessing nested hashes? [duplicate] (4 answers) Closed 3 years ago . I'm working a little utility written in ruby that makes extensive use of nested hashes. Currently, I'm checking access to nested hash elements as follows: structure = { :a => { :b => 'foo' }} # I want structure[:a][:b] value = nil if structure.has_key?(:a) &&

问题 Let's say I have a hash of hashes data structure constructed as followed: %HoH => ( flintstones => { family_members => "fred;wilma;pebbles;dino", number_of_members => 4, }, jetsons => { family_members => "george;jane;elroy", number_of_members => 3, }, simpsons => { family_members => "homer;marge;bart;lisa;maggie", number_of_members => 5, }, ) How do I sort the keys, the families in this case, by the value number_of_members from greatest to least? Then I would like to print out the highest two

问题 I have a json structure that I'm decoding that looks like this: person => { city => "Chicago", id => 123, name => "Joe Smith", pets => { cats => [ { age => 6, name => "cat1", type => "siamese", weight => "10 kilos" }, { age => 10, name => "cat2", type => "siamese", weight => "13 kilos" }, ], dogs => [ { age => 7, name => "dog1", type => "siamese", weight => "20 kilos" }, { age => 5, name => "dog2", type => "siamese", weight => "15 kilos" }, ], }, }, } I'm able to print the city , id , name by

问题 Creating hashes of hashes in Ruby allows for convenient two (or more) dimensional lookups. However, when inserting one must always check if the first index already exists in the hash. For example: h = Hash.new h['x'] = Hash.new if not h.key?('x') h['x']['y'] = value_to_insert It would be preferable to do the following where the new Hash is created automatically: h = Hash.new h['x']['y'] = value_to_insert Similarly, when looking up a value where the first index doesn't already exist, it would

问题 I have a hash like: h = {'name' => 'sayuj', 'age' => 22, 'project' => {'project_name' => 'abc', 'duration' => 'prq'}} I need a dup of this hash, the change should not affect the original hash. When I try, d = h.dup # or d = h.clone d['name'] = 'sayuj1' d['project']['duration'] = 'xyz' p d #=> {"name"=>"sayuj1", "project"=>{"duration"=>"xyz", "project_name"=>"abc"}, "age"=>22} p h #=> {"name"=>"sayuj", "project"=>{"duration"=>"xyz", "project_name"=>"abc"}, "age"=>22} Here you can see the

问题 Is there any way simpler than if hash.key?('a') hash['a']['b'] = 'c' else hash['a'] = {} hash['a']['b'] = 'c' end 回答1: The easiest way is to construct your Hash with a block argument: hash = Hash.new { |h, k| h[k] = { } } hash['a']['b'] = 1 hash['a']['c'] = 1 hash['b']['c'] = 1 puts hash.inspect # "{"a"=>{"b"=>1, "c"=>1}, "b"=>{"c"=>1}}" This form for new creates a new empty Hash as the default value. You don't want this: hash = Hash.new({ }) as that will use the exact same hash for all