Ruby

Get the Index of a JSON Member

See more JSON Examples

This example demonstrates how to get the index of a given member by name.

{
  "name": "donut",
  "image":
    {
    "fname": "donut.jpg",
    "w": 200,
    "h": 200
    },
  "thumbnail":
    {
    "fname": "donutThumb.jpg",
    "w": 32,
    "h": 32
    }
}

Ruby

require 'chilkat'

success = false

json = Chilkat::CkJsonObject.new()

# This is the above JSON with whitespace chars removed (SPACE, TAB, CR, and LF chars).
# The presence of whitespace chars for pretty-printing makes no difference to the Load
# method. 
jsonStr = "{\"name\": \"donut\",\"image\":{\"fname\": \"donut.jpg\",\"w\": 200,\"h\": 200},\"thumbnail\":{\"fname\": \"donutThumb.jpg\",\"w\": 32,\"h\": 32}}"

success = json.Load(jsonStr)
if (success == false)
    print json.lastErrorText() + "\n";
    exit
end

# The top-level JSON object has three members: name, image, and thumbnail.
nameIndex = json.IndexOf("name")
# The index of the "name" member is 0.
print "nameIndex = " + nameIndex.to_s() + "\n";

thumbIndex = json.IndexOf("thumbnail")
# The index of the "thumbnail" member is 2.
print "thumbIndex = " + thumbIndex.to_s() + "\n";

# The "fname" member is NOT a direct member of the top-level JSON object.
# It is a member of a nested object.  If we try to get the index of this
# member using the top-level JSON object, it is not found (and returns -1).
fnameIndex = json.IndexOf("fname")
# The fnameIndex is -1 (not found).  This is correct.
print "fnameIndex = " + fnameIndex.to_s() + "\n";

# Get the "image" object.
imageObj = Chilkat::CkJsonObject.new()
json.ObjectOf2("image",imageObj)

# Now we can get the index of the "fname" object, because it is a direct
# member of the "image" object:
fnameIndex = imageObj.IndexOf("fname")
print "fnameIndex = " + fnameIndex.to_s() + "\n";