Can someone please explain JSON to me?
Complex JSON nesting of objects and arrays
java - How to create JSON Object using String? - Stack Overflow
How do I make a JSON object with multiple arrays? - Stack Overflow
Videos
I've never worked with any DB or back-end, etc stuff, but I am in need of some sort of data storage. I'm working on a javascript application that will only be run on my pc, offline, and I need to be able to save information. I don't want to rely on localStorage because if the browser history is wiped then all the data goes with it.
While searching for a way to collect and store info, I read about JSON, and it sounded like what I was looking for--and yet I've spent the last 4 hours watching tutorials and so far all I know about it is it's fching JS. I sat through a 12 minute video where all the guy did was write out an object in json and then copy and paste into a js file and said "now you know how to use json in all your future projects" 🙄 like what in ACTUAL fk. You could have just WROTE that in js. What's the point of JSON? Everything I've seen or read is practically just the same as this video.
DOES json collect and store data?
Like, if I put an input form in my app, and type a name and hit submit, can I make that Input hardcode into the json file to be saved forevermore and called upon when I needed in this app? Because that's what I need. Any explanation or help on this would be GREATLY appreciated.
The first code is an example of Javascript code, which is similar, however not JSON. JSON would not have 1) comments and 2) the var keyword
You don't have any comments in your JSON, but you should remove the var and start like this:
orders: {
The [{}] notation means "object in an array" and is not what you need everywhere. It is not an error, but it's too complicated for some purposes. AssociatedDrug should work well as an object:
"associatedDrug": {
"name":"asprin",
"dose":"",
"strength":"500 mg"
}
Also, the empty object labs should be filled with something.
Other than that, your code is okay. You can either paste it into javascript, or use the JSON.parse() method, or any other parsing method (please don't use eval)
Update 2 answered:
obj.problems[0].Diabetes[0].medications[0].medicationsClasses[0].className[0].associatedDrug[0].name
returns 'aspirin'. It is however better suited for foreaches everywhere
I successfully solved my problem. Here is my code:
The complex JSON object:
{
"medications":[{
"aceInhibitors":[{
"name":"lisinopril",
"strength":"10 mg Tab",
"dose":"1 tab",
"route":"PO",
"sig":"daily",
"pillCount":"#90",
"refills":"Refill 3"
}],
"antianginal":[{
"name":"nitroglycerin",
"strength":"0.4 mg Sublingual Tab",
"dose":"1 tab",
"route":"SL",
"sig":"q15min PRN",
"pillCount":"#30",
"refills":"Refill 1"
}],
"anticoagulants":[{
"name":"warfarin sodium",
"strength":"3 mg Tab",
"dose":"1 tab",
"route":"PO",
"sig":"daily",
"pillCount":"#90",
"refills":"Refill 3"
}],
"betaBlocker":[{
"name":"metoprolol tartrate",
"strength":"25 mg Tab",
"dose":"1 tab",
"route":"PO",
"sig":"daily",
"pillCount":"#90",
"refills":"Refill 3"
}],
"diuretic":[{
"name":"furosemide",
"strength":"40 mg Tab",
"dose":"1 tab",
"route":"PO",
"sig":"daily",
"pillCount":"#90",
"refills":"Refill 3"
}],
"mineral":[{
"name":"potassium chloride ER",
"strength":"10 mEq Tab",
"dose":"1 tab",
"route":"PO",
"sig":"daily",
"pillCount":"#90",
"refills":"Refill 3"
}]
}
],
"labs":[{
"name":"Arterial Blood Gas",
"time":"Today",
"location":"Main Hospital Lab"
},
{
"name":"BMP",
"time":"Today",
"location":"Primary Care Clinic"
},
{
"name":"BNP",
"time":"3 Weeks",
"location":"Primary Care Clinic"
},
{
"name":"BUN",
"time":"1 Year",
"location":"Primary Care Clinic"
},
{
"name":"Cardiac Enzymes",
"time":"Today",
"location":"Primary Care Clinic"
},
{
"name":"CBC",
"time":"1 Year",
"location":"Primary Care Clinic"
},
{
"name":"Creatinine",
"time":"1 Year",
"location":"Main Hospital Lab"
},
{
"name":"Electrolyte Panel",
"time":"1 Year",
"location":"Primary Care Clinic"
},
{
"name":"Glucose",
"time":"1 Year",
"location":"Main Hospital Lab"
},
{
"name":"PT/INR",
"time":"3 Weeks",
"location":"Primary Care Clinic"
},
{
"name":"PTT",
"time":"3 Weeks",
"location":"Coumadin Clinic"
},
{
"name":"TSH",
"time":"1 Year",
"location":"Primary Care Clinic"
}
],
"imaging":[{
"name":"Chest X-Ray",
"time":"Today",
"location":"Main Hospital Radiology"
},
{
"name":"Chest X-Ray",
"time":"Today",
"location":"Main Hospital Radiology"
},
{
"name":"Chest X-Ray",
"time":"Today",
"location":"Main Hospital Radiology"
}
]
}
The jQuery code to grab the data and display it on my webpage:
$(document).ready(function() {
var items = [];
$.getJSON('labOrders.json', function(json) {
$.each(json.medications, function(index, orders) {
$.each(this, function() {
$.each(this, function() {
items.push('<div class="row">'+this.name+"\t"+this.strength+"\t"+this.dose+"\t"+this.route+"\t"+this.sig+"\t"+this.pillCount+"\t"+this.refills+'</div>'+"\n");
});
});
});
$('<div>', {
"class":'loaded',
html:items.join('')
}).appendTo("body");
});
});
org.json.JSONArray may be what you want.
String message;
JSONObject json = new JSONObject();
json.put("name", "student");
JSONArray array = new JSONArray();
JSONObject item = new JSONObject();
item.put("information", "test");
item.put("id", 3);
item.put("name", "course1");
array.put(item);
json.put("course", array);
message = json.toString();
// message
// {"course":[{"id":3,"information":"test","name":"course1"}],"name":"student"}
In contrast to what the accepted answer proposes, the documentation says that for JSONArray() you must use put(value) no add(value).
https://developer.android.com/reference/org/json/JSONArray.html#put(java.lang.Object)
(Android API 19-27. Kotlin 1.2.50)
On the outermost level, a JSON object starts with a { and end with a }.
Sample data:
{
"cars": {
"Nissan": [
{"model":"Sentra", "doors":4},
{"model":"Maxima", "doors":4},
{"model":"Skyline", "doors":2}
],
"Ford": [
{"model":"Taurus", "doors":4},
{"model":"Escort", "doors":4}
]
}
}
If the JSON is assigned to a variable called data, then accessing it would be like the following:
data.cars['Nissan'][0].model // Sentra
data.cars['Nissan'][1].model // Maxima
data.cars['Nissan'][2].doors // 2
for (var make in data.cars) {
for (var i = 0; i < data.cars[make].length; i++) {
var model = data.cars[make][i].model;
var doors = data.cars[make][i].doors;
alert(make + ', ' + model + ', ' + doors);
}
}
Another approach (using an associative array for car models rather than an indexed array):
{
"cars": {
"Nissan": {
"Sentra": {"doors":4, "transmission":"automatic"},
"Maxima": {"doors":4, "transmission":"automatic"}
},
"Ford": {
"Taurus": {"doors":4, "transmission":"automatic"},
"Escort": {"doors":4, "transmission":"automatic"}
}
}
}
data.cars['Nissan']['Sentra'].doors // 4
data.cars['Nissan']['Maxima'].doors // 4
data.cars['Nissan']['Maxima'].transmission // automatic
for (var make in data.cars) {
for (var model in data.cars[make]) {
var doors = data.cars[make][model].doors;
alert(make + ', ' + model + ', ' + doors);
}
}
Edit:
Correction: A JSON object starts with { and ends with }, but it's also valid to have a JSON array (on the outermost level), that starts with [ and ends with ].
Also, significant syntax errors in the original JSON data have been corrected: All key names in a JSON object must be in double quotes, and all string values in a JSON object or a JSON array must be in double quotes as well.
See:
- JSON specification
- JSONLint - The JSON validator
A good book I'm reading: Professional JavaScript for Web Developers by Nicholas C. Zakas 3rd Edition has the following information regarding JSON Syntax:
"JSON Syntax allows the representation of three types of values".
Regarding the one you're interested in, Arrays it says:
"Arrays are represented in JSON using array literal notation from JavaScript. For example, this is an array in JavaScript:
var values = [25, "hi", true];
You can represent this same array in JSON using a similar syntax:
[25, "hi", true]
Note the absence of a variable or a semicolon. Arrays and objects can be used together to represent more complex collections of data, such as:
{
"books":
[
{
"title": "Professional JavaScript",
"authors": [
"Nicholas C. Zakas"
],
"edition": 3,
"year": 2011
},
{
"title": "Professional JavaScript",
"authors": [
"Nicholas C.Zakas"
],
"edition": 2,
"year": 2009
},
{
"title": "Professional Ajax",
"authors": [
"Nicholas C. Zakas",
"Jeremy McPeak",
"Joe Fawcett"
],
"edition": 2,
"year": 2008
}
]
}
This Array contains a number of objects representing books, Each object has several keys, one of which is "authors", which is another array. Objects and arrays are typically top-level parts of a JSON data structure (even though this is not required) and can be used to create a large number of data structures."
To serialize (convert) a JavaScript object into a JSON string you can use the JSON object stringify() method. For the example from Mark Linus answer:
var cars = [{
color: 'gray',
model: '1',
nOfDoors: 4
},
{
color: 'yellow',
model: '2',
nOfDoors: 4
}];
cars is now a JavaScript object. To convert it into a JSON object you could do:
var jsonCars = JSON.stringify(cars);
Which yields:
"[{"color":"gray","model":"1","nOfDoors":4},{"color":"yellow","model":"2","nOfDoors":4}]"
To do the opposite, convert a JSON object into a JavaScript object (this is called parsing), you would use the parse() method. Search for those terms if you need more information... or get the book, it has many examples.
The second is almost correct:
Copy{
"foos" : [{
"prop1":"value1",
"prop2":"value2"
}, {
"prop1":"value3",
"prop2":"value4"
}]
}
The first example from your question,
Copyfoos: [
foo: { ... },
foo: { ... }
]
is in invalid syntax. You cannot have object properties inside a plain array.
The second example from your question,
Copyfoos: [
{ ... },
{ ... }
]
is right although it is not strict JSON. It's a relaxed form of JSON wherein quotes in string keys are omitted.
Following is the correct one when you want to obey strict JSON:
Copy"foos": [
{ ... },
{ ... }
]
This "Mastering JSON" tutorial by Patrick Hunlock, may help to learn about JSON and this site may help to validate JSON.