import ballerina/io;function main (string[] args) {
    json j1 = [1, false, null, "foo",
               {first:"John", last:"Pala"}];
    io:println(j1);
    json j2 = j1[4];
    io:println(j2.first);
    j1[4] = 8.00;
    io:println(j1);
    json p = {
                 fname:"John", lname:"Stallone",
                 family:[{fname:"Peter", lname:"Stallone"},
                         {fname:"Emma", lname:"Stallone"},
                         {fname:"Jena", lname:"Stallone"},
                         {fname:"Paul", lname:"Stallone"}]
             };
    p.family[2].fname = "Alisha";
    io:println(p);
    json family = p.family;
    int l = lengthof family;
    io:println("length of array: " + l);
    int i = 0;
    while (i < l) {
        io:println(family[i]);
        i = i + 1;
    }
}

JSON Arrays

JSON array literals are written exactly the same way as Ballerina arrays. JSON array values must be of type string, number, object, array, boolean, or null.

import ballerina/io;
function main (string[] args) {
    json j1 = [1, false, null, "foo",
               {first:"John", last:"Pala"}];
    io:println(j1);

JSON Arrays. They are arrays of any JSON value.

    json j2 = j1[4];
    io:println(j2.first);

Access JSON array elements by index.

    j1[4] = 8.00;
    io:println(j1);

Add or change elements in a JSON array.

    json p = {
                 fname:"John", lname:"Stallone",
                 family:[{fname:"Peter", lname:"Stallone"},
                         {fname:"Emma", lname:"Stallone"},
                         {fname:"Jena", lname:"Stallone"},
                         {fname:"Paul", lname:"Stallone"}]
             };
    p.family[2].fname = "Alisha";
    io:println(p);

JSON array in an object literal.

    json family = p.family;
    int l = lengthof family;
    io:println("length of array: " + l);

Get the length of the JSON array.

    int i = 0;
    while (i < l) {
        io:println(family[i]);
        i = i + 1;
    }
}

Loop through the array.

$ ballerina run json-arrays.bal
[1,false,null,"foo",{"first":"John","last":"Pala"}]
John
[1,false,null,"foo",8.0]
{"fname":"John","lname":"Stallone",
 "family":[{"fname":"Peter","lname":"Stallone"},
           {"fname":"Emma","lname":"Stallone"},
           {"fname":"Alisha","lname":"Stallone"},
           {"fname":"Paul","lname":"Stallone"}]}
length of array: 4
{"fname":"Peter","lname":"Stallone"}
{"fname":"Emma","lname":"Stallone"}
{"fname":"Alisha","lname":"Stallone"}
{"fname":"Paul","lname":"Stallone"}

At the command line, navigate to the directory that contains the .bal file and run the ballerina run command.