I have the current JSON file:
[{"id":"1","images":[{"img_id":"1"},{"img_id":"2"},{"img_id":"3"}]},
[{"id":"2","images":[{"img_id":"1"},{"img_id":"2"},{"img_id":"3"}]}
How do I select the array with ID 1 and list every 'img_id' inside it, without repeating it for the other array?
edit 1:
I am trying to parse it like this but this code is erroneous:
$("#button").click(function() {
$.getJSON("../path/to/json", function(data) {
$.each(data[0].images.img_id, function(i,data){
var new_data ="<p src='path/to/folder/"+images.img_id+"'></p>";
$(new_data).appendTo("#htmlTag");
});
}); return false;
});
Much appreciated.
You have an array of objects, where each object contains another array of objects. I'm assuming the JSON structure you are using is:
var a = [{"id":"1","images":[{"img_id":"1"},{"img_id":"2"},{"img_id":"3"}]},
{"id":"2","images":[{"img_id":"1"},{"img_id":"2"},{"img_id":"3"}]}];
I'm also assuming you are using JavaScript.
PostEdit:
Your code is fairly close, I believe what I have below should work:
$("#button").click(function() {
$.getJSON("../path/to/json", function(data) {
$.each(data[0].images, function(i,data){
var new_data ="<p src='path/to/folder/" + data.img_id + "'></p>";
$(new_data).appendTo("#htmlTag");
});
});
return false;
});
All I did was change the first parameter to your each call from: data[0].images.img_id to: data[0].images. Also, I changed the declaration of new_data from:
var new_data ="<p src='path/to/folder/"+images.img_id+"'></p>";
to:
var new_data ="<p src='path/to/folder/"+data.img_id+"'></p>";
Note that the parameter "data" in the each callback function is simply the element in the array, while "i" is the index of that element in the array. Therefore, data is an object which looks like this:
{"img_id":1}
So, you can get the ID via data.img_id. Hope this helps.
I think you're talking about references. I don't think they are possible in JSON. In case you strictly need them and still want the readable serialization of your objects - I'd suggest you to look into YAML
I think there is a typo in your JSON...it seems like a bracket is missing at the end, and one has been added at the start of line 2. But, assuming you meant this (and are using Javascript):
var myJson = [{"id":"1","images":[{"img_id":"1"},{"img_id":"2"},{"img_id":"3"}]},
{"id":"2","images":[{"img_id":"1"},{"img_id":"2"},{"img_id":"3"}]}];
then you can access whatever you need just like a nested Javascript object. If you wanted to only access the object with ID equal to 1, and order is not guaranteed, you would have to iterate:
for(var i = 0; i < myJson.length; i++){
if(myJson[i].id === "1"){
var imgs = myJson[i].images;
for(var j = 0; j < imgs.length; j++){
//do what you want with imgs[j].img_id
}
}
}
Related
I have a computed array which is full of tags and updates depending on what selection i make in the select box. I would like to take this array and pass it to a method and then run a method to update what “results” have an active class. Although I get an array saying I can’t run forEach on this element.
Been through a few topics and understand computed properties dont work like that but surely there is a way around this.
https://jsfiddle.net/39jb3fzw/6/
Short Snippet
methods: {
updateOutput() {
var tags = this.tagArray;
tags.forEach(function(tag) {
console.log(tag);
})
}
},
computed: {
concatenated: function () {
var ret = this.selected.concat(this.selected2, this.selected3);
this.tagArray = ret;
//this.updateOutput();
return ret;
}
}
Full Output
https://jsfiddle.net/39jb3fzw/6/
Thanks again :slight_smile:
It looks like the issue is the line:
var ret = this.selected.concat(this.selected2, this.selected3);
That line of code is returning an empty string rather than an array. This is because this.selectedX is a string rather than an Array. This explains why tag.forEach is undefined. forEach doesn't exist on the String prototype.
You can create this an array instead be doing
var ret = [ this.selected, this.selected2, this.selected3 ]
From there you can set this.tagArray to ret
Hope this helps
I am learning how to build apps and working with Swift for this project.
I had a buddy help me pull data in from a website and it looks like he created classes with variables and mapped them to certain extensions (IE "Username") so when I call the variable data such as profile I would call it. The below uses luck_30 able to store "Stats.luck_30"
luck_30.text = profile.luck_30
So inside one of my variables that is in this "Profile" class is setup into an array. I can pull the array out of the class, but I can't seem to do for while statement replacing the [#] with a variable from the for command.
func aliveWorkers(profile: Profile) -> NSNumber{
var myworkers : Array = profile.workers!
//this test works and returns the proper value
var testworker: NSNumber = myworkers[0].alive!
println("The satus of the test worker is " + testworker.description)
/* This code is giving error "Could not find member alive" it does not ifor var
for ifor in myworkers{
var thisworker: NSNumber = myworkers[ifor].alive! as NSNumber
}
*/
return 42
}
Your variable ifor is not a counter, it is an actual object. You could do something like this:
for worker in myWorkers {
let workerIsAlive = worker.alive!
}
Alternatively, if you need the index,
for i in 0 ..< myWorkers.count {
let worker = myWorkers[i]
let workerIsAlive = worker.alive!
}
If you need both:
for (i, worker) in enumerate(myWorkers) {
let workerIsAlive = worker.alive!
}
And as a matter of style, I would stay away from NSNumber and use Int or Bool or whatever the data actually is. Also, it looks like the alive variable should not be optional, as you're unwrapping it everywhere. To avoid "mysterious" crashes later, you may want to think about making it a non-optional type.
when using a for in loop, your loop variable isn't an index, its the objects you're looping through. so..
func aliveWorkers() {
var myworkers = [1, 2, 3]
//this test works and returns the proper value
let testworker = myworkers[0]
print("The satus of the test worker is \(testworker)")
for ifor in myworkers {
print(ifor)
}
}
Notice a few things... you don't need to use + to concatenate those strings. you can just use string interpolation. \(variable) inserts the value of variable in the string.
Try to use let instead of var when you don't change the variable. You don't need to explicitly define type on variables either.
I have an array of objects like so:
[{}, {}, {}]
I need to pass this array via Socket.io. Socket.io converts the array into JSON and I keep getting the circular structure to JSON error.
Heres my current code:
for (var i = 0; i < 5; i++) {
num = randRange(0, cards[type].length);
playerCards.push(cards[type][num]);
}
socket.emit('updateCards', playerCards);
Does anyone know a way around this?
Thanks
You would see the same error if you tried to do the following:
for (var i = 0; i < 5; i++) {
num = randRange(0, cards[type].length);
playerCards.push(cards[type][num]);
JSON.stringify(cards[type][num])
}
//socket.emit('updateCards', playerCards);
The tag attribute is likely the culprit. In order for the JSON serializer to work you cannot have any circular references in the object being serialized. One option would be to pull out the information needed from the tag object and create a custom object instead.
friends. I have the following issue. I have two observable arrays.
self.NamesArray= ko.observableArray([{"name: John"}, {"name: Mario"}]);
and
self.ValueArray = ko.observable([]);
I would like to loop through the NamesArray and add only the name values to the ValueArray.
So the output ValueArray should contain the following elements in the end:
{John, Mario}
How can this happen? I am very new to JS and I am just researching the Knockout library. Any help with working example will be greatly appreciated. Thanks.
Fiddle: http://jsfiddle.net/PsyComa/RfWVP/
This really depends on your intention behind doing this.
If you want do to this just once, simply iterate over the first array:
// Load current values of the observables
var n = self.NamesArray(), v = self.ValueArray();
// Push all names from n to v
for (var i = 0; i < n.length; i++) {
v.push( n[i].name );
}
// Update the "values" observable
self.ValueArray(v);
The downside with this is that "ValueArray" does not get updated whenever "NamesArray" changes. If you want "ValueArray" to be an array containing all names that can be found in "NamesArray" (and only those!), you can use a computed observable instead:
self.ValueArray = ko.computed(function() {
var n = self.NamesArray(), v = [];
// ...same for loop as above...
return v;
});
Here's what I'm currently doing/trying to do to accomplish my goal. But it is not removing the "row" the way I would like it too.
So, I'm making an object, then pushing it into an array. And the adding to the array part works fine and just as I expect.
var nearProfileInfoObj:Object = new Object();
nearProfileInfoObj.type = "userInfo";
nearProfileInfoObj.dowhat = "add";
nearProfileInfoObj.userid = netConnection.nearID;
nearProfileInfoObj.username = username_input_txt.text;
nearProfileInfoObj.sex = sex_input_txt.selectedItem.toString();
nearProfileInfoObj.age = age_input_txt.selectedItem;
nearProfileInfoObj.location = location_input_txt.text;
nearProfileInfoObj.headline = headline_input_txt.text;
theArray.push(nearProfileInfoObj);
So after that later on I need to be able to remove that object from the array, and it's not working the way I'm expecting. I want to take a variable whoLeft and capture their ID and then look in the array for that particular ID in the userid part of the object and if its there DELETE that whole "row".
I know you can do a filter with an array collection but that doesnt actually delete it. I need to delete it because I may be adding the same value again later on.
whoLeft = theiruserIDVariable;
theArray.filter(userLeaving);
public function userLeaving(element:*, index:int, arr:Array):Boolean
{
if (element.userid == whoLeft)
{
return false;
}
else
{
return true;
}
}
But this doesnt seem to be deleting the whole row like it implies. Does anyone know what i'm doing wrong?
Instead of modifying the original array, the new filtered array is returned by the filter method. So you need to assign the returned array to theArray.
Try this
theArray = theArray.filter(userLeaving);
EDIT This turned out to be slower than for loop:
An alternative to the hand coded loop could be something like this:
theArray.every(searchAndDestroy);
public function searchAndDestroy(element:*, index:int, arr:Array):Boolean
{
if (element.userid == whoLeft)
{
arr.splice(index,1);
return false;
}
return true;
}
As far as I know, every() terminates the first time the test function returns false. So the question is: for a big list, which is faster, the for loop or the loop that every() does with the overhead of the test function call.
EDIT #2 But this was faster than a for loop for a test I ran on an array of a million Points:
for each(var element:Object in theArray)
{
if (element.userid==whoLeft)
{
theArray.splice(theArray.indexOf(element),1);
break;
}
}
I think this is what you're looking for:
for(var i:uint = 0, len:uint = theArray.length; i<len; i++)
{
if(thisArray[i].id == whoLeft.id)
{
thisArray.splice(i, 1);
break;
}
}
However, do you really need it in an Array because you could always use a Dictionary which would mean accessing it by id which would be a lot simpler to remove.