Parsing nested JSON data

ruby-talk
1

Hi,
I didn't find a mailing list dedicated to ruby-json, so I assume that
this would be
the correct place to ask.

From a web API, I receive a JSON stream such as:

[{“u”:“http://…html”,“d”:“some title”,“t”:[“ruby”]},
{“u”:“http://…org/”,“d”:“another title”,“t”:
[“ruby”,“json”,“library”]},…]

Now, among the rest, I also want to access those "ruby", "json" and
"library" strings.
With the following code:

@structs = JSON.parse(@json_stream)

for i in 0...@structs.length
  @struct_obj = @structs.fetch(i)
  @struct_obj.each { |key, value|
    if key == "t"
      # get the value that 't' points to
    end
  }
end

I get them all appended to each other without any whitespace, ie
"rubyjsonlibrary".

How could I access them individually?

Marko

2

Marko Anastasov wrote:

Now, among the rest, I also want to access those "ruby", "json" and
"library" strings.
With the following code:

@structs = JSON.parse(@json_stream)

for i in 0...@structs.length
  @struct_obj = @structs.fetch(i)
  @struct_obj.each { |key, value|
    if key == "t"
      # get the value that 't' points to
    end
  }
end

I get them all appended to each other without any whitespace, ie
"rubyjsonlibrary".

How could I access them individually?

Marko

for i in 0...@structs.length
  @struct_obj = @structs.fetch(i)
  @struct_obj.each { |key, value|
    if key == "t"
      # get the value that 't' points to

         #the value that t points to is stored in your 'value' variable
          value.each do |str|
            puts str
          end

···

    end
  }
end

--
Posted via http://www.ruby-forum.com/\.

3

7stud probably covered your question, so if you don't mind I'd like to
hijack this thread and ask a more general question about JSON
parsing...

Is it possible that JSON could be built into Ruby? The syntax is so
close to Ruby's as of 1.9, that it seems a small step and rather a
shame not to just go ahead and make it compatible. Off hand it seems
that only quoted keys are missing.

T.

···

On Nov 23, 7:30 pm, Marko Anastasov <marko.anasta...@gmail.com> wrote:

From a web API, I receive a JSON stream such as:

[{"u":"http://…html",“d”:“some title","t":["ruby"]},
{"u":"http://…org/”,“d”:"another title","t":
["ruby","json","library"]},...]

Now, among the rest, I also want to access those "ruby", "json" and
"library" strings.
With the following code:

@structs = JSON.parse(@json_stream)

for i in 0...@structs.length
  @struct_obj = @structs.fetch(i)
  @struct_obj.each { |key, value|
    if key == "t"
      # get the value that 't' points to
    end
  }
end

I get them all appended to each other without any whitespace, ie
"rubyjsonlibrary".

How could I access them individually?

4

7stud -- wrote:

         #the value that t points to is stored in your 'value' variable
          value.each do |str|
            puts str
          end

Whoops. Never mind. I'm not even sure why anyone would use the
ruby-json gem. There's no documentation anywhere, and after I installed
it, I couldn't even require it into a program without error.

···

--
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5

7stud -- wrote:

There's no documentation anywhere, and after I installed
it, I couldn't even require it into a program without error.

Look how easy it is with the json gem:

require 'rubygems'
require 'json'

str = '[
{"u":"http://…html",“d”:“some title","t":["ruby"]},
{"u":"http://…org/”,“d”:"another
title","t":["ruby","json","library"]}
]'

arr = JSON.parse(str)
p arr
puts

target_hash = arr[1]
target_hash.each do |key, val|
  if key == 't'
    val.each {|elmt| puts elmt}
  end
end

--output:--
[{"d"=>"some title", "t"=>["ruby"], "u"=>"http://…html"},
{"d"=>"another title", "t"=>["ruby", "json", "library"],
"u"=>"http://…org/"}]

ruby
json
library

···

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6

Thanks a lot 7stud. I didn't realize that each val (as in your last
code snippet) is an array.

···

On Nov 24, 8:05 am, 7stud -- <bbxx789_0...@yahoo.com> wrote:

7stud -- wrote:
> There's no documentation anywhere, and after I installed
> it, I couldn't even require it into a program without error.

Look how easy it is with the json gem:

require 'rubygems'
require 'json'

str = '[
{"u":"http://…html",“d”:“some title","t":["ruby"]},
{"u":"http://…org/”,“d”:"another
title","t":["ruby","json","library"]}
]'

arr = JSON.parse(str)
p arr
puts

target_hash = arr[1]
target_hash.each do |key, val|
  if key == 't'
    val.each {|elmt| puts elmt}
  end
end

--output:--
[{"d"=>"some title", "t"=>["ruby"], "u"=>"http://…html"},
{"d"=>"another title", "t"=>["ruby", "json", "library"],
"u"=>"http://…org/"}]

ruby
json
library
--
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