(Swift 3,4,5...) JSON Paths

Demonstrates using "Chilkat JSON Paths" to access parts of a JSON document, or to iterate over parts.

This example uses the following JSON document:

{
    "nestedArray" : [
			[
				[1,2,3],
				[4,5,6],
				[7,8,9,10]
			],
			[
				[11,12,13],
				[14,15,16],
				[17,18,19,20]
			],
			[
				[21,22,23],
				[24,25,26],
				[27,28,29,30],
				[31,32,33,34,35,36]
			]
		],

	"nestedObject" : {
		"aaa" : {
			"bb1" : {
				"cc1" : "c1Value",
				"cc2" : "c2Value",
				"cc3" : "c3Value"
			},
			"bb2" : {
				"dd1" : "d1Value",
				"dd2" : "d2Value",
				"dd3" : "d3Value"
			}
		}
	},

	"mixture" : {
		"arrayA" : [  
			{ "fruit": "apple", "animal": "horse", "job": "fireman", "colors": ["red","blue","green"] },
			{ "fruit": "pear", "animal": "plankton", "job": "waiter", "colors": ["yellow","orange","purple"] },
			{ "fruit": "kiwi", "animal": "echidna", "job": "astronaut", "colors": ["magenta","tan","pink"] }
			]
	},


        "name.with.dots" : { "grain" : "oats" }

	
}

Chilkat Downloads for the Swift Programming Language MAC OS X (Cocoa) Objective-C/Swift Libs iOS Objective-C/Swift Libs

func chilkatTest() {
    let json = CkoJsonObject()!
    json.emitCompact = false

    // Assume the file contains the data as shown above..
    var success: Bool = json.loadFile("qa_data/json/pathSample.json")
    if success != true {
        print("\(json.lastErrorText!)")
        return
    }

    // First, let's get the value of "cc1"
    // The path to this value is: nestedObject.aaa.bb1.cc1
    print("\(json.string(of: "nestedObject.aaa.bb1.cc1")!)")

    // Now let's get number 18 from the nestedArray.
    // It is located at nestedArray[1][2][1]
    // (remember: Indexing is 0-based)
    print("This should be 18: \(json.int(of: "nestedArray[1][2][1]").intValue)")

    // We can do the same thing in a more roundabout way using the 
    // I, J, and K properties.  (The I,J,K properties will be convenient
    // for iterating over arrays, as we'll see later.)
    json.i = 1
    json.j = 2
    json.k = 1
    print("This should be 18: \(json.int(of: "nestedArray[i][j][k]").intValue)")

    // Let's iterate over the array containing the numbers 17, 18, 19, 20.
    // First, use the SizeOfArray method to get the array size:
    var sz: Int = json.size(ofArray: "nestedArray[1][2]").intValue
    // The size should be 4.
    print("size of array = \(sz) (should equal 4)")

    // Now iterate...
    var i: Int
    for i = 0; i <= sz - 1; i++ {
        json.i = i
        print("\(json.int(of: "nestedArray[1][2][i]").intValue)")
    }

    // Let's use a triple-nested loop to iterate over the nestedArray:
    var j: Int
    var k: Int

    // szI should equal 1.
    var szI: Int = json.size(ofArray: "nestedArray").intValue
    for i = 0; i <= szI - 1; i++ {
        json.i = i

        var szJ: Int = json.size(ofArray: "nestedArray[i]").intValue
        for j = 0; j <= szJ - 1; j++ {
            json.j = j

            var szK: Int = json.size(ofArray: "nestedArray[i][j]").intValue
            for k = 0; k <= szK - 1; k++ {
                json.k = k

                print("\(json.int(of: "nestedArray[i][j][k]").intValue)")
            }

        }

    }

    // Now let's examine how to navigate to JSON objects contained within JSON arrays.
    // This line of code gets the value "kiwi" contained within "mixture"
    print("\(json.string(of: "mixture.arrayA[2].fruit")!)")

    // This line of code gets the color "yellow"
    print("\(json.string(of: "mixture.arrayA[1].colors[0]")!)")

    // Getting an object at a path:
    // This gets the 2nd object in "arrayA"
    var obj2: CkoJsonObject? = json.object(of: "mixture.arrayA[1]")
    // This object's "animal" should be "plankton"
    print("\(obj2!.string(of: "animal")!)")

    // Note that paths are relative to the object, not the absolute root of the JSON document.
    // Starting from obj2, "purple" is at "colors[2]"
    print("\(obj2!.string(of: "colors[2]")!)")

    obj2 = nil

    // Getting an array at a path:
    // This gets the array containing the colors red, green, blue:
    var arr1: CkoJsonArray? = json.array(of: "mixture.arrayA[0].colors")
    var szArr1: Int = arr1!.size.intValue
    for i = 0; i <= szArr1 - 1; i++ {
        print("\(i): \(arr1!.string(at: i)!)")
    }

    arr1 = nil

    // The Chilkat JSON path uses ".", "[", and "]" chars for separators.  When a name
    // contains one of these chars, use double-quotes in the path:
    print("\(json.string(of: "\"name.with.dots\".grain")!)")

}