This question already has answers here:
Remove duplicates form an array
(17 answers)
Closed 5 years ago.
I have this array?
var arr = [{id:"1",Name:"Tom"},
{id:"2",Name:"Jon"},
{id:"3",Name:"Tom"},
{id:"4",Name:"Jack"}]
From array above I need to fecth all existing Names distinct.
var result = getNamesDistinct(arr);
The result should contain result is:
["Tom","Jon","Jack"];
My question is how to get all existing Names from arr distinct?
If Set is available, you can simply do
new Set(arr.map(obj => obj.Name))
(pass the set to Array.from if you need an array)
You can do it via Set object
const arr = [
{ id: "1", Name: "Tom" },
{ id: "2", Name: "Jon" },
{ id: "3", Name: "Tom" },
{ id: "4", Name: "Jack" }
];
const uniqueNames = [...new Set(arr.map(item => item.Name))];
console.log(uniqueNames);
Or you can iterate over the array and add condition to get only unique names.
const arr = [
{ id: "1", Name: "Tom" },
{ id: "2", Name: "Jon" },
{ id: "3", Name: "Tom" },
{ id: "4", Name: "Jack" }
];
const uniqueNames = arr.reduce(function(arr, item) {
if(arr.indexOf(item.Name) === -1) {
arr.push(item.Name);
}
return arr;
}, []);
console.log(uniqueNames);
you can try this
var array = [{
id: "1",
Name: "Tom"
}, {
id: "2",
Name: "Jon"
}, {
id: "3",
Name: "Tom"
}, {
id: "4",
Name: "Jack"
}]
function uniqueNames(array) {
var newArray = [];
array.forEach((value, key) => {
newArray.push(value.Name)
});
return newArray
}
var myNewArray = uniqueNames(array)
Related
I have an array of objects, each array has a key of name and then another array of objects:
const myArray = [ { name: "1", item: [{}] }, { name: "2", item: [{}] }, { name: "1", item: [{}] } ]
Now for example sometimes that name key will be the same, i want to be able to check if that name exists and if it does exist push the item into that array object and not into a new object.
The behaviour im getting is above but i would like:
const myArray = [ { name: "1", item: [{ item1, item2 etc }] }, { name: "2", item: [{}] }, { name: "3", item: [{}] } ]
Thanks so much in advance!
You can get the desired result using Array.reduce(), grouping by name.
If two objects in myArray share the same name, the item values are combined.
const myArray = [ { name: "1", item: [{ id: 1 }] }, { name: "2", item: [{ id: 2}] }, { name: "1", item: [{ id: 3}] } ]
const result = Object.values(myArray.reduce((acc, { name, item }) => {
acc[name] = acc[name] || { name, item: [] };
acc[name].item.push(...item);
return acc;
}, {}))
console.log('Result:', result)
.as-console-wrapper { max-height: 100% !important; }
Here's a solution using Array.prototype.reduce function.
const myArray = [ { name: "1", item: [{}] }, { name: "2", item: [{}] }, { name: "1", item: [{}] } ];
const output = myArray.reduce((acc, curr) => {
const index = acc.findIndex(pre => pre.name === curr.name);
if(index !== -1) {
acc[index].item = acc[index].item.concat(curr.item);
} else {
acc.push(curr);
}
return acc;
}, []);
console.log(output);
This question already has answers here:
Group array items using object
(19 answers)
How can I group an array of objects by key?
(32 answers)
Closed 7 months ago.
I want to make this
const arr = [
{
"name": "mac"
},
{
"group": "others",
"name": "lenovo"
},
{
"group": "others",
"name": "samsung"
}
]
into this:
[
{
name: 'mac',
},
{
name: 'others',
group: [
{
name: 'lenovo',
},
{
name: 'samsung',
},
],
}
]
I tried to use normal forEach loop but it didn't turn out well:
let final = []
const result = arr.forEach(o => {
if(o.group) {
group = []
group.push({
name: o.name
})
final.push(group)
} else {
final.push(o)
}
});
Not sure if reduce might help? before I try lodash groupBy I want to use just pure js to try to make it.
Hope this answer will work for you.
const arr = [
{
name: "mac",
},
{
group: "others",
name: "lenovo",
},
{
group: "others",
name: "samsung",
},
];
const temp = [];
arr.forEach((e) => {
if (!e.group) {
temp.push(e);
} else {
const index = temp.findIndex((ele) => ele.name === e.group);
if (index === -1) {
obj = {
name: e.group,
group: [{ name: e.name }],
};
temp.push(obj)
} else {
temp[index].group.push({ name: e.name });
}
}
});
console.log(temp);
instead of creating and pushing group array in final again and again u should just push group in the end of foreach
like this--
let final = []
let group = []
const result = arr.forEach(o => {
if(o.group) {
group.push({
name: o.name
})
} else {
final.push(o)
}
})
final.push({name: "others", group})
I want to return an array of objects without any duplicate ids. If there are any, then take the first one we see. So, we should NOT see {id: "2", value: '10'}. Instead, the value should be "Italian". I have this code below, but I am getting an map.has is not a function error.
const arr1 = [{
id: "1",
value: "English"
},
{
id: "2",
value: "Italian"
}
];
const arr2 = [{
id: "2",
value: '10'
},
{
id: "3",
value: "German"
}
];
const concatArr = arr1.concat(arr2);
const mergedArr = [...concatArr.reduce((map, obj) => map.has(obj.id) ? "" : map.set(obj.id, obj), new Map()).values()];
console.log(mergedArr);
You need to always return a map not an empty string when the thing is already in the map.
const arr1 = [{
id: "1",
value: "English"
},
{
id: "2",
value: "Italian"
}
];
const arr2 = [{
id: "2",
value: '10'
},
{
id: "3",
value: "German"
}
];
const concatArr = arr1.concat(arr2);
const mergedArr = [...concatArr.reduce((map, obj) => map.has(obj.id) ? map : map.set(obj.id, obj), new Map()).values()];
console.log(mergedArr);
You can use array#reduce to uniquely identify each object with unique id in an object accumulator and then extract all values from this object using Object.values().
const arr1 = [{ id: "1", value: "English" }, { id: "2", value: "Italian" } ],
arr2 = [{ id: "2", value: '10' }, { id: "3", value: "German" } ],
result = Object.values(arr1.concat(arr2).reduce((r, o) => {
r[o.id] = r[o.id] || o;
return r;
},{}));
console.log(result);
Is there any way i can filter files with given extension and then further filter them
for eg: I have .txt extension and i want to get all my .txt from an array
file=
[ "animal_bio.txt",
"xray.pdf",
"fish_bio.txt",
"mammal_doc.txt",
"human_bio.txt",
"machine.jpg"
]
filtered output contain all .txt extension and further it should contain all the files which have _bio.txt name in it.
so output look like
futherFile=
[ "human_bio.txt",
"fish_bio.txt",
"animal_bio.txt"
]
You can use String.protytype.endsWith function to compare the strings with your extension
const file =
[ "animal_bio.txt",
"xray.pdf",
"fish_bio.txt",
"mammal_doc.txt",
"human_bio.txt",
"machine.jpg"
]
result = file.filter((fileName) => fileName.endsWith("_bio.txt"));
console.log(result)
You can use the Array.filter method and use the String.endsWith method to filter. An example -
// List of files
file = ["animal_bio.txt",
"xray.pdf",
"fish_bio.txt",
"mammal_doc.txt",
"human_bio.txt",
"machine.jpg"
]
// Filtering by extension
file.filter(x => x.endsWith(".txt"));
Hope it helped :)
You can easily achieve this result using reduce and match
When matching for the doc or bio, You can even restrict more to get the string only if _doc.txt is at end of the string using Regular expression /_bio.txt$/
const arr = [
{
id: "1",
name: "animal_bio.txt",
},
{
id: "2",
name: "xray.pdf",
},
{
id: "3",
name: "animal_doc.txt",
},
{
id: "4",
name: "fish_doc.txt",
},
{
id: "5",
name: "flower_petals.jpg",
},
{
id: "5",
name: "plant_roots.jpg",
},
{
id: "6",
name: "human_image.jpg",
},
{
id: "7",
name: "human_bio.txt",
},
{
id: "8",
name: "mammal_doc.txt",
},
];
const result = arr.reduce((acc, { name }) => {
if (name.match(/\.txt$/)) {
if (name.match(/_bio/)) {
acc[0].push(name);
} else {
acc[1].push(name);
}
}
return acc;
},
[[], []]
);
console.log(result);
Then you can get the element containing doc and bio using array destructuring as
const [bioArr, docArr] = result;
console.log(bioArr);
console.log(docArr);
const arr = [
{
id: "1",
name: "animal_bio.txt",
},
{
id: "2",
name: "xray.pdf",
},
{
id: "3",
name: "animal_doc.txt",
},
{
id: "4",
name: "fish_doc.txt",
},
{
id: "5",
name: "flower_petals.jpg",
},
{
id: "5",
name: "plant_roots.jpg",
},
{
id: "6",
name: "human_image.jpg",
},
{
id: "7",
name: "human_bio.txt",
},
{
id: "8",
name: "mammal_doc.txt",
},
];
const result = arr.reduce(
(acc, { name }) => {
if (name.match(/\.txt$/)) {
if (name.match(/_bio/)) {
acc[0].push(name);
} else {
acc[1].push(name);
}
}
return acc;
},
[[], []]
);
const [bioArr, docArr] = result;
console.log(bioArr);
console.log(docArr);
you can use filter function from ES6 like:
const txtFile = file.filter((item) => (item.split('_'))[1] === 'bio.txt')
This question already has answers here:
Merge specific properties of objects together with JavaScript
(3 answers)
Closed 3 years ago.
I would like to know how to combine array values if same id in javascript.
I tried below code
let result = this.getData(obj);
function getData(obj) {
return obj.map(e=>({procode: e.prcode, id: e.id});
}
var obj= [
{
id: "1",
prcode: "dessert"
},{
id: "1",
prcode: "snacks"
}, {
id: "2",
prcode: "cafe"
}, {
id: "4",
prcode: "all"
}
]
Expected Output:
result = [
{id: "1", prcode: "dessert,snacks"},
{id: "2", prcode: "cafe"},
{id: "4", prcode: "all"}
]
You can use reduce alongside Object.values():
var obj = [
{ id: "1", prcode: "dessert" },
{ id: "1", prcode: "snacks" },
{ id: "2", prcode: "cafe" },
{ id: "4", prcode: "all" }
]
const out = obj.reduce((a, v) => {
if(a[v.id]) {
a[v.id].prcode = [a[v.id].prcode, v.prcode].join(',')
} else {
a[v.id] = v
}
return a
}, {})
console.log(Object.values(out))