JSON
Arrays
Arrays as
JSON Objects
Example
[
"Ford", "BMW", "Fiat" ]
Arrays in
JSON are almost the same as arrays in JavaScript.
In JSON,
array values must be of type string, number, object, array, boolean or null.
In
JavaScript, array values can be all of the above, plus any other valid
JavaScript expression, including functions, dates, and undefined.
Arrays in
JSON Objects
Arrays can
be values of an object property:
Example
{
"name":"John",
"age":30,
"cars":[
"Ford", "BMW", "Fiat" ]
}
Accessing
Array Values
You access
the array values by using the index number:
Example
x
= myObj.cars[0];
»
Looping
Through an Array
You can
access array values by using a for-in loop:
Example
for
(i in myObj.cars) {
x += myObj.cars[i];
}
»
Or you can
use a for loop:
Example
for
(i = 0; i < myObj.cars.length; i++) {
x += myObj.cars[i];
}
»
Nested
Arrays in JSON Objects
Values in an
array can also be another array, or even another JSON object:
Example
myObj
= {
"name":"John",
"age":30,
"cars": [
{ "name":"Ford",
"models":[ "Fiesta", "Focus", "Mustang"
] },
{ "name":"BMW",
"models":[ "320", "X3", "X5" ] },
{ "name":"Fiat",
"models":[ "500", "Panda" ] }
]
}
To access
arrays inside arrays, use a for-in loop for each array:
Example
for
(i in myObj.cars) {
x += "<h1>" +
myObj.cars[i].name + "</h1>";
for (j in myObj.cars[i].models) {
x += myObj.cars[i].models[j];
}
}
»
Modify Array
Values
Use the
index number to modify an array:
Example
myObj.cars[1] = "Mercedes";
»
Delete Array
Items
Use the
delete keyword to delete items from an array:
Example
delete
myObj.cars[1];
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