Ruby JSON node select, view & value change [duplicate] - ruby

Question

This question already has an answer here:
How to convert JSON to a hash, search for and change a value
(1 answer)
Closed 7 years ago.
I am trying to select a node from a JSON parsed file and display the node/key hierarchy by using dots to separate the nodes.
json_hash =
{
"Samples": {
"Locations": {
"Presets": "c:\\Presets\\Inst",
"Samples": "c:\\Samples\\seperates\\round_robin"
},
"Format": {
"Type": "AIFF",
"Samplerate": 48,
"Bitrate": 24
},
"Groupings": {
"Type": "dynamic",
"Sets": {
"Keyswitch": "enabled",
"Mods": "Enabled"
}
},
"Ranges": {
"Keys": {
"LowKey": 30,
"HighKey": 80,
"LowVel": 0,
"MidVel": 53,
"HighVel": 127
}
},
"Dynamics": {
"DN": {
"MultiRange": "enabled",
"Range": [
"0-36",
"37-80"
]
}
}
},
"Modulation": {
"Pitch": true,
"Range": []
},
"Encoded": false,
"test": "test_one"
}
My idea is to output something like this;
Samples.Locations.Presets => c:\Presets\Inst
Samples.Locations.Samples => c:\Samples\seperates\round_robin
I managed to get this;
Presets. => c:\Presets\Inst
Presets.Samples. => c:\Samples\seperates\round_robin
Using this code:
def node_tree(hash)
kl = ''
hash.each do |k, v|
kl << "#{k}."
if v.kind_of?(Hash)
node_tree(v)
else
print "#{kl} => "
print "#{Array(v).join(', ')}\n"
end
end
end
node_tree(json_hash)
It would be great if I could get the full node hierarchy to display and then be able to select a node using dot separated node and change the value.
So I could change the Samples.Dynamics.DN.Range from 0-36, 37-80 to 0-30, 31-60, 61-90
key = 'Samples.Dynamics.DN.Range'
value = %w(0-30 31-60 61-90)
node_set('Samples.Dynamics.DN.Range', value)
I can't work on the later until I figure out how best to display and select the nodes and values.

Answer 1

Using this method you can flatten the hash:
def flat_hash(hash, k = [])
return { k => hash } unless hash.is_a?(Hash)
hash.inject({}) { |h, v| h.merge! flat_hash(v[-1], k + [v[0]]) }
end
p flat_hash(json_hash)
#=> {["Samples", "Locations", "Presets"]=>"c:\\Presets\\Inst", ["Samples", "Locations", "Samples"]=>"c:\\Samples\\seperates\\round_robin", ["Samples", "Format", "Type"]=>"AIFF", ["Samples", "Format", "Samplerate"]=>48, ["Samples", "Format", "Bitrate"]=>24, ["Samples", "Groupings", "Type"]=>"dynamic", ["Samples", "Groupings", "Sets", "Keyswitch"]=>"enabled", ["Samples", "Groupings", "Sets", "Mods"]=>"Enabled", ["Samples", "Ranges", "Keys", "LowKey"]=>30, ["Samples", "Ranges", "Keys", "HighKey"]=>80, ["Samples", "Ranges", "Keys", "LowVel"]=>0, ["Samples", "Ranges", "Keys", "MidVel"]=>53, ["Samples", "Ranges", "Keys", "HighVel"]=>127, ["Samples", "Dynamics", "DN", "MultiRange"]=>"enabled", ["Samples", "Dynamics", "DN", "Range"]=>["0-36", "37-80"], ["Modulation", "Pitch"]=>true, ["Modulation", "Range"]=>[], ["Encoded"]=>false, ["test"]=>"test_one"}
Using regular expression for valid path /([A-Z|a-z]:\\[^*|"<>?\n]*)|(\\\\.*?\\.*)/ you can filter flatten hash:
VALID_PATH_REGEXP = /([A-Z|a-z]:\\[^*|"<>?\n]*)|(\\\\.*?\\.*)/
flat_hash(json_hash).each_pair do |k, v|
puts "#{Array(k).join('.')} => #{v}" if v.to_s =~ VALID_PATH_REGEXP
end
#=> Samples.Locations.Presets => c:\Presets\Inst
#=> Samples.Locations.Samples => c:\Samples\seperates\round_robin
Final code:
require 'json'
VALID_PATH_REGEXP = /([A-Z|a-z]:\\[^*|"<>?\n]*)|(\\\\.*?\\.*)/
json_hash = JSON.parse(File.read('example.json'))
def flat_hash(hash, k = [])
return { k => hash } unless hash.is_a?(Hash)
hash.inject({}) { |h, v| h.merge! flat_hash(v[-1], k + [v[0]]) }
end
flat_hash(json_hash).each_pair do |k, v|
puts "#{Array(k).join('.')} => #{v}" if v.to_s =~ VALID_PATH_REGEXP
end
#=> Samples.Locations.Presets => c:\Presets\Inst
#=> Samples.Locations.Samples => c:\Samples\seperates\round_robin
Update:
That's probably better to return hash with the results, rather than just printing them:
require 'json'
VALID_PATH_REGEXP = /([A-Z|a-z]:\\[^*|"<>?\n]*)|(\\\\.*?\\.*)/
json_hash = JSON.parse(File.read('example.json'))
def flat_hash(hash, k = [])
return { k => hash } unless hash.is_a?(Hash)
hash.inject({}) { |h, v| h.merge! flat_hash(v[-1], k + [v[0]]) }
end
def node_tree(hash)
flat_hash(hash).map { |k, v| [Array(k).join('.'), v] if v.to_s =~ VALID_PATH_REGEXP }.compact.to_h
end
p node_tree(json_hash)
#=> {"Samples.Locations.Presets"=>"c:\\Presets\\Inst", "Samples.Locations.Samples"=>"c:\\Samples\\seperates\\round_robin"}