Lua Requires Chilkat v11.0.0+

Modify Parts of JSON Document

See more JSON Examples

Demonstrates how to modify parts of a JSON document. This example uses the following JSON document:

{
   "fruit": [
      	{
         "kind": "apple",
	 "count": 24,
	 "fresh": true,
	 "extraInfo": null,
	 "listA": [ "abc", 1, null, false ],
	 "objectB": { "animal" : "monkey" }
      	},
	{
         "kind": "pear",
	 "count": 18,
	 "fresh": false,
	 "extraInfo": null
	 "listA": [ "xyz", 24, null, true ],
	 "objectB": { "animal" : "lemur" }
	}
    ],
    "list" : [ "banana", 12, true, null, "orange", 12.5, { "ticker": "AAPL" }, [ 1, 2, 3, 4, 5 ] ],
    "alien" : true
}

Lua

local chilkat = require("chilkat")

local json = chilkat.JsonObject.new()

-- Load the JSON from a file.
local success = json:load_file("qa_data/json/modifySample.json")
if not success then
    print(json.last_error_text)
    return
end

-- This example will not check for errors (i.e. null / false / 0 return values)...

-- Get the "list" array:

local listA = chilkat.JsonArray.new()

json:array_of2("list", listA)

-- Modify values in the list.

-- Change banana to plantain
success = listA:set_string_at(0, "plantain")

-- Change 12 to 24
success = listA:set_int_at(1, 24)

-- Change true to false
success = listA:set_bool_at(2, false)

-- Is the 3rd item null?
local bNull = listA:is_null_at(3)

-- Change "orange" to 32.
success = listA:set_int_at(4, 32)

-- Change 12.5 to 31.2
success = listA:set_number_at(5, "31.2")

-- Replace the { "ticker" : "AAPL" } object with { "ticker" : "GOOG" }
-- Do this by deleting, then inserting a new object at the same location.
success = listA:delete_at(6)
local tickerObj = chilkat.JsonObject.new()
listA:add_object_at2(6, tickerObj)

success = tickerObj:append_string("ticker", "GOOG")

-- Replace "[ 1, 2, 3, 4, 5 ]" with "[ "apple", 22, true, null, 1080.25 ]"
success = listA:delete_at(7)
local aa = chilkat.JsonArray.new()
listA:add_array_at2(7, aa)

success = aa:add_string_at(-1, "apple")
success = aa:add_int_at(-1, 22)
success = aa:add_bool_at(-1, true)
success = aa:add_null_at(-1)
success = aa:add_number_at(-1, "1080.25")

-- Get the "fruit" array
local aFruit = chilkat.JsonArray.new()
json:array_at2(0, aFruit)

-- Get the 1st element:
local appleObj = chilkat.JsonObject.new()
aFruit:object_at2(0, appleObj)

-- Modify values by member name:
success = appleObj:set_string_of("fruit", "fuji_apple")
success = appleObj:set_int_of("count", 46)
success = appleObj:set_bool_of("fresh", false)
success = appleObj:set_string_of("extraInfo", "developed by growers at the Tohoku Research Station in Fujisaki")

-- Modify values by index:

local pearObj = chilkat.JsonObject.new()
aFruit:object_at2(1, pearObj)

success = pearObj:set_string_at(0, "bartlett_pear")
success = pearObj:set_int_at(1, 12)
success = pearObj:set_bool_at(2, false)
success = pearObj:set_string_at(3, "harvested in late August to early September")

json.emit_compact = false
print(json:emit())