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So, I am fetching values from a database and then i am returning/using them in JSON/javascript as an array for example as shown here
The problem is that I want the sum of the array elements.
I used this code:
var obj1 = JSON.parse(data);
var mar = obj1.march;
var quantite = obj1.quant;
const sum = quantite.reduce((result,number)=> result+number);
console.log(sum);
And here is what I got in the console
I am totally new into JSON and javascript, so, any tips/help would be great for me!
The elements in the array are strings and so, when you use the + operator it concatenates them. You want to parse them first like this:
const sum = quantite.reduce((result,number)=> parseInt(result) + parseInt(number));
Seems that you data contains strings, not int.
You can improve your reduce function:
quantite.reduce((result,number) => parseInt(result)+parseInt(number));
Use the start value of reduce() and make sure number isn't a string when adding it
quantite.reduce((res,num)=> (res + Number(number)),0);
// start value ^^^
I want to convert a JSON string into a set of array containing the values from the JSON. after json.stringify(jsonmybe) and alert it display [{"role":"noi_user"},{"role":"bert_user"}] (which i saw as a JSON). I want to get the noi_user and bert_user and set them into a javascript array. something like ['noi_user','bert_user'] with quotes in each value.
I did the var stringy = json.parse() and the alert showing [object Object]. and further add this lines
for (var i = 0; i < stringy.length; i++) {
arr.push(stringy[i]['role']);}
and the arr I get was a value with comma when in alert but the comma missing as i display them in the text field and it becomes a long string like noi_userbert_user
What I really want is from [{"role":"noi_user"},{"role":"bert_user"}] to ['noi_user','bert_user']
Use JSON.parse and then reduce to get what you want,
var s = `[{"role":"noi_user"},{"role":"bert_user"}]`
var arr = []
try {
arr = JSON.parse(s).reduce((acc, val)=>[...acc, val.role], [])
} catch (e){
console.log("Invalid json")
}
console.log(arr)
Is this what you are loking for ? You can map on your array and just extract the role attribute of each datum.
const jsonString = ...
const data = JSON.parse(jsonString).map(data => data.role);
console.log(JSON.stringify(data, null, 2));
JSON uses double quotes to delimit strings and field names.
So you have a JSON string like
'[{"role":"noi_user"},{"role":"bert_user"}]'
You want to convert it to an object, then extract values of "role" fields of each element, put them all into an array.
Your example json string contains an array of user objects within "role" fields. Following code takes this list, loops through each user object and puts role's of each object into a separate array roleList.
var jsonStr = '[{"role":"noi_user"},{"role":"bert_user"}]';
var userObjList = JSON.parse(jsonStr);
var roleList = [];
userObjList.forEach(userObj => {
roleList.push(userObj.role);
});
console.log(roleList);
You could make a custom function to produce a sort of array_values in PHP but an indented and 2D level like so:
function array_values_indented (input) {
var tmpArr = []
for (key in input) {
tmpArr.push(input[key]['role']);
}
return tmpArr
}
var object = JSON.parse('[{"role":"noi_user"},{"role":"bert_user"}]');
var result = array_values_indented(object);
console.log(result);
I want to create an array of JSON object without a key.How can this is achieved ..??
for example [{8,0,2}, {20,0,2}].
var hh = 9
var mm = 8
var qty = 2
var data = [];
data.push({hh,mm,qty})
it gives data like [{hh:9,mm:8,qty:2}]
I want array like [{9,8,2},{9,3,4}]
You example uses a new feature of ECMAScript 6 that is the shorthand syntax for initialising object properties. This line in your example:
data.push({hh,mm,qty});
is equivalent to this verbose one:
data.push({hh: hh, mm: mm, qty: qty});
An object in JavaScript will always have keys and values. There is no way to save just values in a plain object. However, there are two other solutions.
One is using an array:
data.push([hh, mm, qty]);
Note the square brackets substituting the curly ones. This will obviously push an array of three values onto the data array. When retrieving the values, you can just refer to their index, as an array's items will always retain their indices:
var data2 = [hh, mm, qty];
var hh2 = data2[0];
var mm2 = data2[1];
var qty2 = data2[2];
Another way of just "saving the values" is using a set, though the construction of a Set object will still require passing it an array:
data.push(new Set([hh, mm, qty]));
Accessing the data is less straightforward in this case, as the set will typically only let you iterate it. Unlike similar data structures in other languages, a JavaScript set will retain the order of inserted values. It can therefore be safely converted into an array:
var mySet = new Set([hh, mm, qty]);
var data3 = Array.from(mySet);
var hh3 = data3[0];
var mm3 = data3[1];
var qty3 = data3[2];
You can read more about sets here.
You can wrap it over another JSON object with a key I assume you want a JSON object.
Like this { [{8,0,2}, {20,0,2}] } but this with a problem - It is not a valid JSON.
I had a similar problem for one of my scenario. Then I realised
A top level JSON can't exist without a key!
Consider this example, you have another KV pair in JSON and also this array.
{
"somekey" : "somevalue",
[ {8,0,2}, {20,0,2} ]
}
You can fetch "somevalue" with the key "somekey". But how would you access the array? you can't :(
I would suggest you to use a top level key for the JSON and make this array as value of it's. Example:
{
"my array" : [ {8,0,2}, {20,0,2} ]
}
Without a key value pair, the object was not created. That's why its adding a key using the variable name
Look at this error. Its invalid code
var a = [{8,0,2}, {20,0,2}];
console.log(a)
You could push to an array instead of an object
var data = [];
var hh = 9
var mm = 8
var qty = 2
var data = [];
data.push([hh,mm,qty])
console.log(data)
You can't.
Object Literal Property Value Shorthands allow you to create an object where the property names are inferred from the variable names you use to pass the data into.
If you don't have variable names, then there is nothing for the JS engine to use to figure out what the property names should be.
Consider using a function instead.
console.log([time(8,0,2), time(20,0,2)]);
function time (hh, mm, qty) {
return {hh, mm, qty};
}
The result you get at the end makes sense. By doing {hh,mm,qty} you are effectively saying "Use the variable name as the key and its value as the value". It might help us more if you provide an example of how you intend to use the result and access the variables i.e. the shape of the object you want in the end.
That being said, there are a couple alternatives:
Using values as the keys
If you really wanted your object to look similar to {8,0,2} you could use those values as the keys (all keys get converted to strings anyways) so you could do the following:
var example1 = {8:undefined,0:undefined,2:undefined};
var example2 = {8:null,0:null,2:null};
var keys = [];
for(var name in example1) {
keys.push(name);
}
// keys = ["8","0","2"];
var otherKeys = Object.keys(example2);
// otherKeys = ["8","0","2"];
Setting the keys dynamically
var hh = 9;
var mm = 8;
var qty = 2;
var obj = {};
obj[hh] = null;
obj[mm] = null;
obj[qty] = null;
//obj = {9:null,8:null,2:null};
I'm not certain if this solves your problem or answers your question entirely but it might give you some more insight into what is happening and why. The above examples are a common way to create a quick lookup versus a dictionary with would have values in place of null or undefined.
I have a string with values i want to use. I'm parsing this string as an JSON object using $.parseJSON. However I'm having problems getting the actual values.
In this case I'm trying to get the value of the key "textarea1" which is "banana". What is the correct syntax for getting the values. I tried obj.texts.textarea1, but it didn't work.
The string looks like this:
var obj = "[{\"texts\":[{\"default\":true,\"bread-texts\":false,\"textarea1\":\"Banana\",\"textarea2\":\"Kiwi\",\"textarea3\":\Apple\",\"textarea4\":\"coffe\",\"textarea5\":\"Tea\",\"signature\":true,\"profile\":\"header\",\"fontsize\":\"26\",\"fontsize-headers\":\"10.5\",\"fontcolor\":\"#0000\",\"textfont\":\"header-large\",\"textsub1\":\"Bold\",\"font\":\"ICA%20Text\",\"textsub\":\"Regular\",\"textsize\":\"20\",\"textsize-signature\":\"9.5\",\"textsizesmall\":\"5.5\",\"textsizesmall-placer\":\"2.75\",\"vers-placer\":\"false\",\"text-colored\":\"%23000000\",\"s-all-customers\":true,\"new-customers\":true,\"undefined\":\"\"}]}]";
Script:
var oldVal = $.parseJSON(obj);
missing quote on \Apple
You access obj but need to access oldVal
you have nested arrays so you need array notation to get at them or flatten the arrays
You do not need jQuery and likely have not defined it. JSON.parse will work
var obj = "[{\"texts\":[{\"default\":true,\"bread-texts\":false,\"textarea1\":\"Banana\",\"textarea2\":\"Kiwi\",\"textarea3\":\"Apple\",\"textarea4\":\"coffe\",\"textarea5\":\"Tea\",\"signature\":true,\"profile\":\"header\",\"fontsize\":\"26\",\"fontsize-headers\":\"10.5\",\"fontcolor\":\"#0000\",\"textfont\":\"header-large\",\"textsub1\":\"Bold\",\"font\":\"ICA%20Text\",\"textsub\":\"Regular\",\"textsize\":\"20\",\"textsize-signature\":\"9.5\",\"textsizesmall\":\"5.5\",\"textsizesmall-placer\":\"2.75\",\"vers-placer\":\"false\",\"text-colored\":\"%23000000\",\"s-all-customers\":true,\"new-customers\":true,\"undefined\":\"\"}]}]";
var oldVal = JSON.parse(obj);
console.log(oldVal[0].texts[0].textarea1)
If you want to access oldVal.texts.textarea1 you need to remove the array:
var obj = "{\"texts\":{\"default\":true,\"bread-texts\":false,\"textarea1\":\"Banana\",\"textarea2\":\"Kiwi\",\"textarea3\":\"Apple\",\"textarea4\":\"coffe\",\"textarea5\":\"Tea\",\"signature\":true,\"profile\":\"header\",\"fontsize\":\"26\",\"fontsize-headers\":\"10.5\",\"fontcolor\":\"#0000\",\"textfont\":\"header-large\",\"textsub1\":\"Bold\",\"font\":\"ICA%20Text\",\"textsub\":\"Regular\",\"textsize\":\"20\",\"textsize-signature\":\"9.5\",\"textsizesmall\":\"5.5\",\"textsizesmall-placer\":\"2.75\",\"vers-placer\":\"false\",\"text-colored\":\"%23000000\",\"s-all-customers\":true,\"new-customers\":true,\"undefined\":\"\"}}";
1st Option
You need not to change anything. Just fix your JSON in correct format.
You can use JsonLint to check your JSON is correct or not. Then Proceed further.
var obj = "[{\"texts\":[{\"default\":true,\"bread-texts\":false,\"textarea1\":\"Banana\",\"textarea2\":\"Kiwi\",\"textarea3\":\"Apple\",\"textarea4\":\"coffe\",\"textarea5\":\"Tea\",\"signature\":true,\"profile\":\"header\",\"fontsize\":\"26\",\"fontsize-headers\":\"10.5\",\"fontcolor\":\"#0000\",\"textfont\":\"header-large\",\"textsub1\":\"Bold\",\"font\":\"ICA%20Text\",\"textsub\":\"Regular\",\"textsize\":\"20\",\"textsize-signature\":\"9.5\",\"textsizesmall\":\"5.5\",\"textsizesmall-placer\":\"2.75\",\"vers-placer\":\"false\",\"text-colored\":\"%23000000\",\"s-all-customers\":true,\"new-customers\":true,\"undefined\":\"\"}]}]";
var oldVal = JSON.parse(obj);
alert(oldVal[0].texts[0].textarea1)
2nd Option
If you want to get the result like obj.texts.textarea1 then you'll have to change your data as following.
Format Your JSON
Remove all [ and ] from your json.
then do.
var a = '{"texts": {"default": true,"bread-texts": false,"textarea1": "Banana","textarea2": "Kiwi","textarea3": "Apple","textarea4": "coffe","textarea5": "Tea","signature": true,"profile": "header","fontsize": "26","fontsize-headers": "10.5","fontcolor": "#0000","textfont": "header-large","textsub1": "Bold","font": "ICA%20Text","textsub": "Regular","textsize": "20","textsize-signature": "9.5","textsizesmall": "5.5","textsizesmall-placer": "2.75","vers-placer": "false","text-colored": "%23000000","s-all-customers": true,"new-customers": true,"undefined": ""} }';
var obj = JSON.parse(a);
Then
obj.texts.textarea1;
You've created array in your JSON so for that you need to do array accessing.
obj is of type string. You can not index it as object in the form obj.texts. You are parsing it using $.parseJSON, then use the object returned by that call:
var oldVal = $.parseJSON( obj );
var value = oldVal[0].texts[0].textarea1;
Your JSON is invalid.
At this place, you are missing a quote:
\"textarea3\":\Apple\" (escaped)
"textarea3":Apple" (unescaped)
JSON parsing will fail at this point.
After fixing this typo, I can easily access your JSON items this way:
var obj = "[{\"texts\":[{\"default\":true,\"bread-texts\":false,\"textarea1\":\"Banana\",\"textarea2\":\"Kiwi\",\"textarea3\":\"Apple\",\"textarea4\":\"coffe\",\"textarea5\":\"Tea\",\"signature\":true,\"profile\":\"header\",\"fontsize\":\"26\",\"fontsize-headers\":\"10.5\",\"fontcolor\":\"#0000\",\"textfont\":\"header-large\",\"textsub1\":\"Bold\",\"font\":\"ICA%20Text\",\"textsub\":\"Regular\",\"textsize\":\"20\",\"textsize-signature\":\"9.5\",\"textsizesmall\":\"5.5\",\"textsizesmall-placer\":\"2.75\",\"vers-placer\":\"false\",\"text-colored\":\"%23000000\",\"s-all-customers\":true,\"new-customers\":true,\"undefined\":\"\"}]}]";
// using JSON.parse
document.body.innerHTML = JSON.parse(obj)[0].texts[0].textarea1;
// or using jQuery
document.body.innerHTML += $.parseJSON(obj)[0].texts[0].textarea1;
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
my problem is that i have a json-object with and array into here an example.
var object = {
'items':['entry1','entry2']
}
I want to access 'entry2' over a constant string that I receive and shouldn't be changed.
var string = 'items[1]';
The only way I'm solving this problem is over the eval function...
eval('object.'+string);
This returns me entry2.
Is there any other way to achieve this without using eval()?
Like object[string] or object.string
Supposing your string is always the same form, you could extract its parts using a regex :
var m = string.match(/(\w+)\[(\d+)\]/);
var item = object[m[1]][+m[2]];
Explanation :
The regex builds two groups :
(\w+) : a string
\[(\d+)\] : some digits between brackets
and those groups are at index 1 and 2 of the array returned by match.
+something parses the number. It's not strictly needed here as the array accepts a string if it can be converted but I find the code more readable when this conversion is explicited.
On top of dystroy's anwser, you can use this function:
function getValueFromObject(object, key) {
var m = key.match(/(\w+)\[(\d+)\]/);
return object[m[1]][+m[2]];
}
Example:
var object = {
'items':['entry1','entry2']
}
var string = 'items[1]';
var value = getValueFromObject(object, string); //=> "entry2"
First, you can get the array from inside:
var entries = object.items // entries now is ['entry1','entry2']
Then you need to index that to get the second item (in position 1). So you achieve what you want with:
var answer = entries[1] // answer is now 'entry2'
Of course, you can combine this to get both done in one step:
var answer = object.items[1] // answer is now 'entry2'
... I can see this is a contrived example, but please don't call your Objects 'object', or your Strings 'string' :s
try something like this
object.items[1];