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How to create json object out of two arrays [duplicate]

This question already has answers here:
Create an object from an array of keys and an array of values
(9 answers)
Create object from two arrays
(4 answers)
Closed 2 years ago.
Having two arrays:
let values = ["52", "71", "3", "45", "20", "12", "634", "21"];
let names = ["apple", "orange", "strawberry", "banana", "coconut", "pineapple", "watermelon", "plum"];
How can I create an object like:
{
"apple": 52,
"orange": 71,
"strawberry": 3,
"banana": 45,
"coconut": 20,
"pineapple": 12,
"watermelon": 634,
"plum": 21
}
I tried using Object.assign but this only overrides the values.
Object.assign<any, any>(names, values);
Object.defineProperties doesn't work as well or - more likely - I don't know how to use them.
EDIT
I tried the
let temp = {};
names.forEach((item, index) => {
console.log('item: ', item);
console.log('index: ', index);
console.log('temp[item]: ', temp[item]);
console.log('values[index]: ', values[index]);
temp[item] = values[index];
console.log(names);
});
but this is what I got

Create a new result-object. Add to this object foreach element of names a nnew object with name and corresponding value.
Edited: Because it seems tht you have in your values-array all elements as string and in your result-object the values are integers I use parseInt for convertion.
Note: Using a variable name is not so good because you get an TypeError if you want to use anything like this name.forEach, name.map. It seems it's a reserved word or something like this.
let values = ["52", "71", "3", "45", "20", "12", "634", "21"];
let names = ["apple", "orange", "strawberry", "banana", "coconut", "pineapple", "watermelon", "plum"];
let temp = {};
names.forEach((elem, index) => { temp[elem]=parseInt(values[index]) });
names.forEach((item, index) => {
console.log('item: ', item);
console.log('index: ', index);
console.log('temp[item]: ', temp[item]);
console.log('values[index]: ', values[index]);
temp[item] = values[index];
console.log(names);
});

Match values from one object to another

I have two arrays of objects:
[
0: {key1: value1, key2: value2, key3: value3},
1: {key1: value1, key2: value2, key3: value3}
]
[
0: {stop_id: 173, file_id: "1", key_type: null, key_value: "0020", seg_beg: 32},
1: {stop_id: 176, file_id: "1", key_type: null, key_value: "0201", seg_beg: 10},
2: {stop_id: 176, file_id: "1", key_type: null, key_value: "0201", seg_beg: 10}
]
I need to check to see if the values of any of the keys in the first object, match any of the values of the key_value...keys, in the second object, and then set a variable further up to the stop_id value in the matched record. Like this:
if(object1.value === object2.key_value){
match = object2[iterator].stop_id;
}
To simplify this, I have attempted to just grab the values of the first object:
//pd.segs is object 1
let pdSegValues = [];
for(let i=0;i<pd.segs.length;i++){
pdSegValues.push(Object.values(pd.segs[i]));
}
But that gets me an array of arrays again, and basically puts me back in the same situation. I'm suffering from a fried brain, and admittedly have a weakness for loops. Can anyone show me a decent way to accomplish what I need here?

You can do this by collecting the values you want to test and then using some.
let arr1 = [
{"a1": "value1", "b1": "value2"},
{"a2": "0020", "b2": "value22"},
{"a3": "value111", "b3": "0201"}
];
let arr2 = [
{stop_id: 173, file_id: "1", key_type: null, key_value: "0020", seg_beg: 32},
{stop_id: 176, file_id: "1", key_type: null, key_value: "0201", seg_beg: 10},
{stop_id: 176, file_id: "1", key_type: null, key_value: "0201", seg_beg: 10}
];
// accumulate unique arr1 values to an array
let arr1Values = Array.from(arr1.reduce((acc, curr) => {
Object.values(curr).forEach(v => acc.add(v));
return acc;
}, new Set()));
// accumulate all unique arr2 "key_value"
let arr2KeyValues = arr2.reduce((acc, curr) => {
acc.add(curr.key_value);
return acc;
}, new Set());
console.log(arr1Values);
console.log(Array.from(arr2KeyValues));
// Test if any of the values in objects in the first array are
// equal to any of the key_values in the second array
console.log(arr1Values.some(k => arr2KeyValues.has(k)));

It looks like you're going to have to compare every object in one array to every object's keys in another array. An initial brute force approach has 3 nested for loops:
// Loop through the objects in the first array
for (const objectA of arrayA) {
// Loop through that object's keys
for (const key in objectA) {
// Loop through the objects in the second array
for (const objectB of arrayB) {
if (objectA[key] === objectB.key_value) {
// do all the stuff
}
}
}
}

Here's what I ended up doing, just to leave a record :)
let stopRules = pd.stopRules;
let pdSegs = pd.segs;
let routeStopsTest = [];
//Returns a flat array of all unique values in first object
//Thanks #slider!
let pdSegValues = Array.from(pdSegs.reduce((acc, curr) => {
Object.values(curr).forEach(v => acc.add(v));
return acc;
}, new Set()));
//Pushes all objects from stopRules array to a holding array
//When they match individual segments in the pdSegs array
pdSegValues.forEach( seg => {
let nullTest = stopRules.filter(o => o.key_value === seg);
if(nullTest.length !== 0){
routeStopsTest.push(nullTest);
}else{}
});
Then all I have to do is flatten the resulting array of objects, and I have the results I need, which I can then loop through for the original purpose.
Thank you, everyone, for the insightful input. I've learned a fair bit here :)

Dynamic/computed keys in JMESPath?

From ES2015 with computed properties and Array.reduce/Array.map/Object.assign you can do:
[{name: 'foo', age: 43}, {name: 'bar', age: 55}].map(
o => ({[o.name]: o.age})).reduce((a, b) => Object.assign(a,b), {})
…and get:
{ foo: 43, bar: 55 }
How do I get this from JMESPath?
Attempt:
$echo '[{"name": "foo", "age": 43}, {"name": "bar", "age": 55}]' | jp [].{name:age}
[
{
"name": 43
},
{
"name": 55
}
]

Problem
How to construct a Jmespath query that returns objects with arbitrary key-value pairs
The keys need to be dynamic, based on the output of a jmespath filter expression
Workaround
As of this writing (2019-03-22), dynamic keys are not available in standard Jmespath
However, it is possible to return a list of lists instead of a list of objects, and simply post-process that list of lists outside of jmespath
Example
[*].[#.name,#.age]
Returns
[['foo', 43], ['bar', 55]]
Which can then be post-processed outside of Jmespath, if that is an option for you.
See also
github issue about this exact use-case

To get this result precisely:
{ "foo": 43, "bar": 55 }
You should use this query:
#.{foo: #[0].age, bar: #[1].age}
But as you can see I don't retrieve the keys foo and bar dynamically because I can't do it in JMESPath.

How to extract values from JSON

I get a JSON strings through JSONP call. I just know that how the general structure of JSON is going to be but I do not know what will be the values and keys. The general structure will be like this
[
{"key_name": "value"},
{"key_name": "value"},
{"key_name": "value"}
]
I do not know what will be inside curly brackes. How can I reach these values and change them to something like this
[
{name: "key_name", y: value},
{name: "key_name", y: value},
{name: "key_name", y: value}
]
where value is a number
example fiddle:

Use Array.prototype.map() on the array of objects. Fetch the array of keys of an object using Object.keys()
var x = [{
"key_name1": "25"
}, {
"key_name2": "452"
}, {
"key_name3": "32"
}];
var new_x = x.map(function(el) {
return {
"name": Object.keys(el)[0],
"y": +el[Object.keys(el)[0]]
};
});
console.log(new_x);

Select two fields out of three fields from Json data using Linq.js

I need to select two fields out of three fields from Json data using Linq.js
Required output should be
[{ "A": -27, C: "country 1" } , { "A": 28 , C: "country 2"} ]
using "linq.js" from following path: [ https://raw.github.com/gist/1175460/fb7404d46cab20e31601740ab8b35d99a584f941/linq.js ]
Sample data
var Data = [{ "A": -27, "B": -39, C: "country 1" }, { "A": 28, "B": 0 , C: "country 2"}]
var filter = " x => x['A'], x['C'] ";
var findItem = Enumerable.From(Data)
.Select(filter)
.ToArray();
console.log(findItem);
code at JsFiddle : http://jsfiddle.net/gLXNw/9/

Your "lambda" function must return a valid java object.
Your query should be more like this:
var query = Enumerable.From(data)
.Select("x => { A: x['A'], X: x['C'] }") // object initializer
.ToArray();

You can use function in result selector instead of lambda (if lambda expression was used not for political reasons :))
var findItem = Enumerable.From(Data)
.Select(function(x){
return {
'A': x['A'],
'X': x['C']
};
}).ToArray();