I have a array like below
data = [A,B,B,B,C,C,A,B]
How can I convert into dictionary like below format.
data = [
{
name: "A",
y: 2
},
{
name: "B",
y: 4
},
{
name: "C",
y: 2
}
]
Have to convert elements as names and count of the elements as value to y.
I've a library which accepts only in that format.
Not able to do, stuck in the middle
Any suggestions are welcome.
data = ['A','B','B','B','C','C','A','B'];
var res = Array.from(new Set(data)).map(a =>
({name:a, y: data.filter(f => f === a).length}));
console.log(res);
use array.reduce:
data = ['A','B','B','B','C','C','A','B'];
var res = data.reduce((m, o) => {
var found = m.find(e => e.name === o);
found ? found.y++ : m.push({name: o, y: 1});
return m;
}, []);
console.log(res);
function convert(data){
var myMap = {}
data.forEach(el => myMap[el] = myMap[el] != undefined ? myMap[el] + 1 : 1);
return Object.keys(myMap).map(k => {return {name: k, y: myMap[k]}})
}
console.log(convert(['A','B','B','B','C','C','A','B']))
Related
I have arr array of objects, I need to pivot it with product,calorie and apply (grouping & sum) on remaining parameters.
And then require data in single object.
I tried below code, it works fine but I divided code in 3 parts.
Could I have better code than this or it is ok.
var arr = [{
"product": "Jam",
"calorie": 2000,
"A": 300,
"B": 500,
"type": "Daily"
},
{
"product": "Sugar",
"calorie": 1000,
"A": 100,
"B": 200,
"type": "Daily"
}
]
var a1 = {}
var a2 = {}
//Step-1 Pivot
for (let i = 0; i < arr.length; i++) {
a1[arr[i]['product']] = arr[i]['calorie'];
}
//Step-2 Group and sum
a2 = groupAndSum(arr, ['type'], ['A', 'B'])[0];
//Step-3 merging.
console.log({ ...a1,
...a2
})
//General grouping and summing function that accepts an
//#Array:Array of objects
//#groupKeys: An array of keys to group by,
//#sumKeys - An array of keys to sum.
function groupAndSum(arr, groupKeys, sumKeys) {
return Object.values(
arr.reduce((acc, curr) => {
const group = groupKeys.map(k => curr[k]).join('-');
acc[group] = acc[group] || Object.fromEntries(groupKeys.map(k => [k, curr[k]]).concat(sumKeys.map(k => [k, 0])));
sumKeys.forEach(k => acc[group][k] += curr[k]);
return acc;
}, {})
);
}
Here a single function which takes 3 params:
const func = (arr, pivot_vals, sum_vals) => {
return arr.reduce((a, v) => {
pivot_vals.forEach((pivot) => {
a[v[pivot[0]]] = v[pivot[1]];
});
sum_vals.forEach((key) => {
if (!a[key]) a[key] = 0;
a[key] += v[key];
});
return a;
},{});
};
arr
containing the data
sum_vals
array with all props you want do be summed
pivot_vals
nested array with the props which should be linked
I wans't sure what to do with the type, since it is a string it can`t be summed. Did you want to count the amount of types ?
let arr = [
{
product: "Jam",
calorie: 2000,
A: 300,
B: 500,
type: "Daily",
},
{
product: "Sugar",
calorie: 1000,
A: 100,
B: 200,
type: "Daily",
},
];
let sum_vals = ["A","B"]
let pivot_vals = [["product", "calorie"]];
const func = (arr, pivot_vals, sum_vals) => {
return arr.reduce((a, v) => {
pivot_vals.forEach((pivot) => {
a[v[pivot[0]]] = v[pivot[1]];
});
sum_vals.forEach((key) => {
if (!a[key]) a[key] = 0;
a[key] += v[key];
});
return a;
},{});
};
console.log(func(arr, pivot_vals, sum_vals));
I have a data that is like following:
const data = [{
ratings: [ { rating: 5 } ],
counts: [ { count: 100 } ],
}];
And I want to flatten it in a sense that I want to get rid of arrays and have only objects, and end result to be:
const data = {
ratings: { rating: 5 },
counts: { count: 100 },
};
I tried to do something like this, but it is wrong and I believe I'm kind of over complicating it.
const flatten = data => {
return data.reduce((r, { ...children }) => {
Object.assign(children, r);
if (children) Object.assign(flatten(...Object.values(children)), r);
return r;
}, {})
}
Any ideas?
You could create recursive function with reduce method to turn all arrays to objects assuming you have just objects in those arrays.
const data = [{ratings: [ { rating: 5 } ],counts: [ { count: 100 } ]}];
function flatten(arr) {
return arr.reduce((r, e) => {
const obj = Object.assign({}, e);
for (let p in obj) {
if (Array.isArray(obj[p])) {
obj[p] = flatten(obj[p])
}
}
return Object.assign(r, obj)
}, {})
}
console.log(flatten(data))
If by any chance the data is result from JSON.parse :
var json = JSON.stringify( [{ratings:[{rating: 5}], counts:[{count: 100}]}] )
var result = JSON.parse(json, (k, v) => v[0] || v)
console.log( result )
Please check:
var data = [{ratings: [ { rating: 5 } ], counts: [ { count: 100 } ]}];
var flatten = function(data) {
if (Array.isArray(data)) {
data = data[0];
for (var key in data) data[key] = flatten(data[key]);
}
return data;
}
console.log(flatten(data));
Please check # CodePen
https://codepen.io/animatedcreativity/pen/842e17d2b9f83bc415513f937fc29be8
I have two list, as bellow:
var a = ["a", "b"]
var b = [{name:"a1", belong_type:"a" }, {name:"a2", belong_type:"a" }, {name:"b1", belong_type:"b" },]
I want to put them like this:
var data = {}
a.forEach(a_item => {
data[a_item] = []
b.forEach(b_item => {
if (a_item === b_item.belong_type){
data[a_item].push(b_item)
}
})
})
console.log(data)
the result is :
{ a:
[ { name: 'a1', belong_task_type: 'a' },
{ name: 'a2', belong_task_type: 'a' } ],
b: [ { name: 'b1', belong_task_type: 'b' } ] }
I think my method use two forEach, I don't know whether there is a better way to realize the result, who can tell me if there is a better way?
You could use reduce method on a array and inside use filter method on b array to return objects where belong_type is equal to current element in reduce.
var a = ["a", "b"]
var b = [{name:"a1", belong_type:"a" }, {name:"a2", belong_type:"a" }, {name:"b1", belong_type:"b" }]
const result = a.reduce((r, e) => {
r[e] = b.filter(({belong_type}) => belong_type == e)
return r;
}, {})
console.log(result)
You could also use Object.assign method inside reduce to write it as a one-liner.
var a = ["a", "b"]
var b = [{name:"a1", belong_type:"a" }, {name:"a2", belong_type:"a" }, {name:"b1", belong_type:"b" }]
const result = a.reduce((r, e) => Object.assign(r, {[e]: b.filter(({belong_type}) => belong_type == e)}), {})
console.log(result)
I need to transmit some data, that has too many key-value pairs.
As the keys are similar, I dont want to transmit them with each object.
Consider I have the following data:
[
{
x:11,
y:12
},{
x:21,
y:22
},{
x:31,
y:32
},{
x:41,
y:42
}
];
And I need the final output as
[ [x,y],[[11,12],[21,22],[31,32],[41,42]] ] OR
[ [x,y],[11,12],[21,22],[31,32],[41,42] ]
On the other end, I should be able to convert back to its original form.
It would be great if it can handle an additional key in some of the objects
I think I have seen lodash or underscore function for something close/similar to this, but I'm not able to find it right now.
NOTE: I don't know what the keys will be
Lodash v4.17.1
modify original
var modifiedOriginal = _.chain(original)
.map(_.keys)
.flatten()
.uniq()
.thru(function(header){
return _.concat(
[header],
_.map(original, function(item) {
return _.chain(item)
.defaults(_.zipObject(
header,
_.times(_.size(header), _.constant(undefined))
))
.pick(header)
.values()
.value()
})
);
})
.value();
modified back to original (keys order is not
guarantee)
var backToOriginal = _.map(_.tail(modified), function(item) {
return _.chain(_.head(modified))
.zipObject(item)
.transform(function(result, val, key) {
if (!_.isUndefined(val)) {
result[key] = val;
}
})
.value();
});
JSFiddle code https://jsfiddle.net/wa8kaL5g/1/
Using Array#reduce
var arr = [{
x: 11,
y: 12
}, {
x: 21,
y: 22
}, {
x: 31,
y: 32
}, {
x: 41,
y: 42
}];
var keys = Object.keys(arr[0]);
var op = arr.reduce(function(a, b) {
var arr = keys.reduce(function(x, y) {
return x.concat([b[y]]);
}, [])
return a.concat([arr]);
}, [keys]); //If all the objects are having identical keys!
console.log(JSON.stringify(op));
A little more verbose way of doing it:
[Edit: added the function to convert it back]
function convert(arr) {
var retArr = [ [/* keys (retArr[0]) */], [/* values (retArr[1]) */] ]
arr.forEach(function(obj){
// create new array for new sets of values
retArr[1].push([])
// put all of the keys in the correct array
for (var key in obj) {
if (obj.hasOwnProperty(key)) {
// does the key exist in the array yet?
if (retArr[0].indexOf(key) === -1) {
retArr[0].push(key)
}
// get last index of retArr[1] and push on the values
retArr[1][retArr[1].length - 1].push(obj[key])
}
}
})
return retArr
}
function reConvert(arr) {
var retArr = []
var keys = arr[0]
arr[1].forEach(function(itemArr){
var obj = {}
itemArr.forEach(function(item, i){
obj[keys[i]] = item
})
retArr.push(obj)
})
return retArr
}
var objArr = [
{
x:11,
y:12
},{
x:21,
y:22
},{
x:31,
y:32
},{
x:41,
y:42
}
]
var arrFromObj = convert(objArr)
var objFromArr = reConvert(arrFromObj)
console.log(arrFromObj)
console.log(objFromArr)
A solution using Underscore.
First work out what the keys are:
var keys = _.chain(data)
.map(_.keys)
.flatten()
.uniq()
.value();
Then map across the data to pick out the value for each key:
var result = [
keys,
_.map(data, item => _.map(keys, key => item[key]))
];
and back again:
var thereAndBackAgain = _.map(result[1], item => _.omit(_.object(result[0], item), _.isUndefined));
Lodash's version of object is zipObject and omit using a predicate is omitBy:
var thereAndBackAgain = _.map(result[1], item => _.omitBy(_.zipObject(result[0], item), _.isUndefined));
var data = [
{
x:11,
y:12,
aa: 9
},{
x:21,
y:22
},{
x:31,
y:32,
z: 0
},{
x:41,
y:42
}
];
var keys = _.chain(data)
.map(_.keys)
.flatten()
.uniq()
.value();
var result = [
keys,
_.map(data, item => _.map(keys, key => item[key]))
];
var thereAndBackAgain = _.map(result[1], item => _.omit(_.object(result[0], item), _.isUndefined));
console.log(result)
console.log(thereAndBackAgain)
<script src="
https://cdnjs.cloudflare.com/ajax/libs/underscore.js/1.8.3/underscore-min.js"></script>
In ES6 you can do it by reducing it with Object.values(), and Object.keys(). You can restore it using a combination of Array.prototype.map() and Array.prototype.reduce():
const convertStructure = (data) => data.reduce((s, item) => {
s[1].push(Object.values(item));
return s;
}, [Object.keys(data[0]), []]); // all objects should be the same, so we can take the keys from the 1st object
const restoreStructure = ([keys, data]) => data.map((item) => item.reduce((o, v, i) => {
o[keys[i]] = v;
return o;
}, {}));
const data = [{
x: 11,
y: 12
}, {
x: 21,
y: 22
}, {
x: 31,
y: 32
}, {
x: 41,
y: 42
}];
const convertedStructure = convertStructure(data);
console.log('convertedStructure:\n', convertedStructure);
const restoredStructure = restoreStructure(convertedStructure);
console.log('restoredStructure:\n', restoredStructure);
I have JSON like
var JObject = [
{
a:"A1",
b:100,
c:800
},
{
a:"B1",
b:300,
c:400
}
];
I need maximum value from this JSON...it has to return 800 if it return key and column index
Since this is tagged in d3.
I will give a d3 answer.
Working code below
var kary = [
{
a:"A1",
b:100,
c:800
},
{
a:"B1",
b:1300,
c:400
},
{
a:"D1",
b:300,
c:400
}
];
var max = d3.max(kary, function(d){ return d3.max(d3.values(d).filter(function(d1){ return !isNaN(d1)}))});
console.log(max)
<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.4.11/d3.min.js"></script>
Hope this helps!
You can do something like this
var JObject = [{
a: "A1",
b: 100,
c: 800
}, {
a: "B1",
b: 300,
c: 400
}];
var res = Math.max.apply(null,JObject.map(function(v) {
// iterate over array element and getting max value from result array
var r = [];
for (var val in v) {
// iterate over object inside array
if (v.hasOwnProperty(val)) {
var num = parseInt(v[val], 10);
// parsing the value for integer output
r.push(isNaN(num) ? 0 : num);
// pushing value to array, in case of `Nan` pushing it as 0
}
}
return Math.max.apply(null,r);
// getting max value from object values
}));
console.log(res);
You could make this more or less generic - and probably shorten it into a single reduce statement.
var data = [
{a:"A1",b:100,c:800},
{a:"B1",b:300,c:400}
];
data
.reduce(function(acc, x, i) {
if (x.b > x.c) {
return acc.concat({key: 'b', value: x.b });
}
return acc.concat({key: 'c', value: x.c });
}, [])
.reduce(function(acc, x, i) {
if (x.value > acc.value) {
return {
key: x.key,
value: x.value,
index: i
};
}
return acc;
}, {key: '', value: Number.MIN_VALUE, index: -1});
If you are using a library like lodash or underscore you can simply do:
_.max(_.map(JObject, function(a){
return _.max(_.values(a));
}));
You can also solve it with reduce:
_.reduce(JObject, function(val, a){
return _.max(_.values(a)) > val ? _.max(_.values(a)) : val;
},0);