I've taken the following sample from a different question. And I am able to identify the object. But I also need to find our the position of that object. For example:
var arr = [{
Id: 1,
Categories: [{
Id: 1
},
{
Id: 2
},
]
},
{
Id: 2,
Categories: [{
Id: 100
},
{
Id: 200
},
]
}
]
If I want to find the object by the Id of the Categories, I can use the following:
var matches = [];
var needle = 100; // what to look for
arr.forEach(function(e) {
matches = matches.concat(e.Categories.filter(function(c) {
return (c.Id === needle);
}));
});
However, I also need to know the position of the object in the array. For example, if we are looking for object with Id = 100, then the above code will find the object, but how do I find that it's the second object in the main array, and the first object in the Categories array?
Thanks!
Well, if every object is unique (only in one of the categories), you can simply iterate over everything.
var arr = [{
Id: 1,
Categories: [{Id: 1},{Id: 2}]
},
{
Id: 2,
Categories: [{Id: 100},{Id: 200}]
}
];
var needle = 100;
var i = 0;
var j = 0;
arr.forEach(function(c) {
c.Categories.forEach(function(e) {
if(e.Id === needle) {
console.log("Entry is in position " + i + " of the categories and in position " + j + " in its category.");
}
j++;
});
j = 0;
i++;
});
function findInArray(needle /*object*/, haystack /*array of object*/){
let out = [];
for(let i = 0; i < haystack.lenght; i++) {
if(haystack[i].property == needle.property) {
out = {pos: i, obj: haystack[i]};
}
}
return out;
}
if you need the position and have to filter over an property of the object you can use a simple for loop. in this sample your result is an array of new object because there can be more mathches than 1 on the value of the property.
i hope it helps
Iterate over the array and set index in object where match found
var categoryGroups = [{
Id : 1,
Categories : [{
Id : 1
}, {
Id : 2
},
]
}, {
Id : 2,
Categories : [{
Id : 100
}, {
Id : 200
},
]
}
]
var filterVal = [];
var needle = 100;
for (var i = 0; i < categoryGroups.length; i++) {
var subCategory = categoryGroups[i]['Categories'];
for (var j = 0; j < subCategory.length; j++) {
if (subCategory[j]['Id'] == findId) {
filterVal.push({
catIndex : i,
subCatIndex : j,
id : needle
});
}
}
}
console.log(filterVal);
Here is solution using reduce:
var arr = [{ Id: 1, Categories: [{ Id: 1 }, { Id: 2 }, ] }, { Id: 2, Categories: [{ Id: 100 }, { Id: 200 }, ] } ]
const findPositions = (id) => arr.reduce((r,c,i) => {
let indx = c.Categories.findIndex(({Id}) => Id == id)
return indx >=0 ? {mainIndex: i, categoryIndex: indx} : r
}, {})
console.log(findPositions(100)) // {mainIndex: 1, categoryIndex: 0}
console.log(findPositions(1)) // {mainIndex: 0, categoryIndex: 0}
console.log(findPositions(200)) // {mainIndex: 1, categoryIndex: 1}
console.log(findPositions(0)) // {}
Beside the given answers with fixt depth searh, you could take an recursive approach by checking the Categories property for nested structures.
function getPath(array, target) {
var path;
array.some(({ Id, Categories = [] }) => {
var temp;
if (Id === target) {
path = [Id];
return true;
}
temp = getPath(Categories, target);
if (temp) {
path = [Id, ...temp];
return true;
}
});
return path;
}
var array = [{ Id: 1, Categories: [{ Id: 1 }, { Id: 2 },] }, { Id: 2, Categories: [{ Id: 100 }, { Id: 200 }] }];
console.log(getPath(array, 100));
.as-console-wrapper { max-height: 100% !important; top: 0; }
I've got the following response from the server:
I want to get the unique key with the occurrence count.
In the following format:
0:{"name":"physics 1","count":2}
1:{"name":"chem 1","count":6}
I've already checked How to count the number of occurrences of each item in an array? but that is not I want.
Here is an es6 solution.
const data = [{
id: 0,
name: 'physics 1',
questionId: 1,
questionNr: 1
}, {
name: 'physics 1',
}, {
name: 'chem 1',
}, {
name: 'chem 1',
}, {
name: 'chem 2',
}];
const grouped = data.reduce((groups, cur) => {
const key = cur.name;
groups[key] = (groups[key] || 0) + 1;
return groups;
}, {});
const result = Object.keys(grouped).map(key => ({name: key, count: grouped[key]}));
console.log(result);
You could do it this way:
var source = [
{'section_name': 'test1'},
{'section_name': 'test2'},
{'section_name': 'test1'},
];
var temp = {};
for (var i = source.length - 1; i >= 0; i--) {
var key = source[i].section_name;
if (!temp[key]) {
temp[key] = 0;
}
temp[key] += 1;
}
var keys = Object.keys(temp);
var result = [];
for (var i = keys.length - 1; i >= 0; i--) {
var key = keys[i];
result.push({"name":key,"count":temp[key]});
}
console.log(result);
use this function this uses map and filter
t.reduce((f,l)=>{
var k=f.filter(elem=>elem.section_name==l.section_name);
if(k.length==1) k[0].count++;
else f.push({section_name:l.section_name,count:1})
return f;
},[] )
you can check this against this to verify
var t=[{section_name:"Physics"},{section_name:"Physics"},{section_name:"Chemistry"},{section_name:"Chemistry"},{section_name:"Physics"}]
I have an 'item' object in JavaScript, and the item can have settings like
color, size, etc.
I need to get all possible combinations in an array.
So lets say we have an item that looks like this:
var newItem = {
name: 'new item',
Settings: [
{name: 'color', values: ['green', 'blue', 'red']},
{name: 'size', values: ['15', '18', '22']},
{name: 'gender',values: ['male', 'female']}
]
};
I need to somehow get this:
[
[{SettingName:'color',value:'green'},{SettingName:'size',value:'15'},{SettingName:'gender',value:'male'}],
[{SettingName:'color',value:'blue'},{SettingName:'size',value:'15'},{SettingName:'gender',value:'male'}],
[{SettingName:'color',value:'red'},{SettingName:'size',value:'15'},{SettingName:'gender',value:'male'}],
[{SettingName:'color',value:'green'},{SettingName:'size',value:'18'},{SettingName:'gender',value:'male'}],
[{SettingName:'color',value:'blue'},{SettingName:'size',value:'18'},{SettingName:'gender',value:'male'}],
[{SettingName:'color',value:'red'},{SettingName:'size',value:'18'},{SettingName:'gender',value:'male'}],
[{SettingName:'color',value:'green'},{SettingName:'size',value:'22'},{SettingName:'gender',value:'male'}],
[{SettingName:'color',value:'blue'},{SettingName:'size',value:'22'},{SettingName:'gender',value:'male'}],
[{SettingName:'color',value:'red'},{SettingName:'size',value:'22'},{SettingName:'gender',value:'male'}],
[{SettingName:'color',value:'green'},{SettingName:'size',value:'15'},{SettingName:'gender',value:'female'}],
[{SettingName:'color',value:'blue'},{SettingName:'size',value:'15'},{SettingName:'gender',value:'female'}],
[{SettingName:'color',value:'red'},{SettingName:'size',value:'15'},{SettingName:'gender',value:'female'}],
[{SettingName:'color',value:'green'},{SettingName:'size',value:'18'},{SettingName:'gender',value:'female'}],
[{SettingName:'color',value:'blue'},{SettingName:'size',value:'18'},{SettingName:'gender',value:'female'}],
[{SettingName:'color',value:'red'},{SettingName:'size',value:'18'},{SettingName:'gender',value:'female'}],
[{SettingName:'color',value:'green'},{SettingName:'size',value:'22'},{SettingName:'gender',value:'female'}],
[{SettingName:'color',value:'blue'},{SettingName:'size',value:'22'},{SettingName:'gender',value:'female'}],
[{SettingName:'color',value:'red'},{SettingName:'size',value:'22'},{SettingName:'gender',value:'female'}]
]
This can be a good interview question.
See JS Bin for running example.
getAllPermutations(newItem);
function getAllPermutations(item) {
var permutations = [];
getAllPermutations0(item, permutations, []);
console.log(permutations);
}
function getAllPermutations0(item, permutations, array) {
if (array && array.length === item.Settings.length) {
permutations.push(array.slice()); // The slice clone the array
return;
}
var index = array.length;
var setting = item.Settings[index];
for (var i = 0; i < setting.values.length; i++) {
if (index === 0)
array = [];
var currValue = setting.values[i];
array.push({
SettingName: setting.name,
value: currValue
});
getAllPermutations0(item, permutations, array);
array.pop(); // pop the old one first
}
}
Here is a none recursive solution. It takes an empty or existing settings "matrix" and a values array, and return a new matrix as a combination of existing matrix content cloned for each new value, appended with pairs of new value setting items.
[A] -> [1,2] gives [A][1][A][2]
[A][1][A][2] -> [X,Y] gives [A][1][X][A][2][Y][A][2][X][A][1][Y]
and so on
function processSettings(settings, name, values) {
if (settings.length == 0) {
values.forEach(function(value) {
settings.push( [{ SettingName: name, value: value }] )
})
} else {
var oldSettings = JSON.parse(JSON.stringify(settings)), settings = [], temp, i = 0
for (i; i<values.length; i++) {
temp = JSON.parse(JSON.stringify(oldSettings))
temp.forEach(function(setting) {
setting.push( { SettingName: name, value: values[i] } )
settings.push(setting)
})
}
}
return settings
}
You can now create the desired settings literal this way :
var settings = []
for (var i=0; i<newItem.Settings.length; i++) {
var item = newItem.Settings[i]
settings = processSettings(settings, item.name, item.values)
}
demo -> http://jsfiddle.net/b4ck98mf/
The above produces this :
[
[{"SettingName":"color","value":"green"},{"SettingName":"size","value":"15"},{"SettingName":"gender","value":"male"}],
[{"SettingName":"color","value":"blue"},{"SettingName":"size","value":"15"},{"SettingName":"gender","value":"male"}],
[{"SettingName":"color","value":"red"},{"SettingName":"size","value":"15"},{"SettingName":"gender","value":"male"}],
[{"SettingName":"color","value":"green"},{"SettingName":"size","value":"18"},{"SettingName":"gender","value":"male"}],
[{"SettingName":"color","value":"blue"},{"SettingName":"size","value":"18"},{"SettingName":"gender","value":"male"}],
[{"SettingName":"color","value":"red"},{"SettingName":"size","value":"18"},{"SettingName":"gender","value":"male"}],
[{"SettingName":"color","value":"green"},{"SettingName":"size","value":"22"},{"SettingName":"gender","value":"male"}],
[{"SettingName":"color","value":"blue"},{"SettingName":"size","value":"22"},{"SettingName":"gender","value":"male"}],
[{"SettingName":"color","value":"red"},{"SettingName":"size","value":"22"},{"SettingName":"gender","value":"male"}],
[{"SettingName":"color","value":"green"},{"SettingName":"size","value":"15"},{"SettingName":"gender","value":"female"}],
[{"SettingName":"color","value":"blue"},{"SettingName":"size","value":"15"},{"SettingName":"gender","value":"female"}],
[{"SettingName":"color","value":"red"},{"SettingName":"size","value":"15"},{"SettingName":"gender","value":"female"}],
[{"SettingName":"color","value":"green"},{"SettingName":"size","value":"18"},{"SettingName":"gender","value":"female"}],
[{"SettingName":"color","value":"blue"},{"SettingName":"size","value":"18"},{"SettingName":"gender","value":"female"}],
[{"SettingName":"color","value":"red"},{"SettingName":"size","value":"18"},{"SettingName":"gender","value":"female"}],
[{"SettingName":"color","value":"green"},{"SettingName":"size","value":"22"},{"SettingName":"gender","value":"female"}],
[{"SettingName":"color","value":"blue"},{"SettingName":"size","value":"22"},{"SettingName":"gender","value":"female"}],
[{"SettingName":"color","value":"red"},{"SettingName":"size","value":"22"},{"SettingName":"gender","value":"female"}]
]
You can use Array.prototype.map(), for loop, while loop, Array.prototype.concat(). Iterate gender values; select each of color, size value in succession beginning at index 0 of either; iterating the furthest adjacent array from current gender, increment the index of the closest adjacent array; merge the resulting two gender arrays to form a single array containing all combinations of gender, color, size
var colors = newItem.Settings[0].values;
var sizes = newItem.Settings[1].values;
var gen = newItem.Settings[2].values;
var i = sizes.length;
var res = [].concat.apply([], gen.map(function(value, key) {
var next = -1;
var arr = [];
for (var curr = 0; curr < i; curr++) {
while (next < i - 1) {
arr.push([{
SettingName: "gender",
value: value
}, {
SettingName: "size",
value: sizes[curr]
}, {
SettingName: "color",
value: colors[++next]
}])
}
next = -1;
}
return arr
}))
var newItem = {
"name": "new item",
"Settings": [{
"name": "color",
"values": [
"green",
"blue",
"red"
]
}, {
"name": "size",
"values": [
"15",
"18",
"22"
]
}, {
"name": "gender",
"values": [
"male",
"female"
]
}]
}
var colors = newItem.Settings[0].values;
var sizes = newItem.Settings[1].values;
var gen = newItem.Settings[2].values;
var i = sizes.length;
var res = [].concat.apply([], gen.map(function(value, key) {
var next = -1;
var arr = [];
for (var curr = 0; curr < i; curr++) {
while (next < i - 1) {
arr.push([{
SettingName: "gender",
value: value
}, {
SettingName: "size",
value: sizes[curr]
}, {
SettingName: "color",
value: colors[++next]
}])
}
next = -1;
}
return arr
}))
document.querySelector("pre").textContent = JSON.stringify(res, null, 2)
<pre></pre>
plnkr http://plnkr.co/edit/C2fOJpfwOrlBwHLQ2izh?p=preview
An approach using Array.prototype.reduce(), Array.prototype.sort(), Object.keys(), for loop, while loop
var newItem = {
name: 'new item',
Settings: [
{
name: 'color',
values: ['green', 'blue', 'red']
},
{
name: 'size',
values: ['15', '18', '22']
},
{
name: 'gender',
values: ['male', 'female']
}
]
};
var props = ["SettingName", "value"];
var settings = newItem.Settings;
function p(settings, props) {
var data = settings.reduce(function(res, setting, index) {
var name = setting.name;
var obj = {};
obj[name] = setting.values;
res.push(obj);
return res.length < index ? res : res.sort(function(a, b) {
return a[Object.keys(a)[0]].length - b[Object.keys(b)[0]].length
})
}, []);
var key = data.splice(0, 1)[0];
return [].concat.apply([], key[Object.keys(key)].map(function(value, index) {
return data.reduce(function(v, k) {
var keys = [v, k].map(function(obj) {
return Object.keys(obj)[0]
});
var i = Math.max.apply(Math, [v[keys[0]].length, k[keys[1]].length]);
var next = -1;
var arr = [];
for (var curr = 0; curr < i; curr++) {
while (next < i - 1) {
var a = {};
a[props[0]] = keys[0];
a[props[1]] = v[keys[0]][++next];
var b = {};
b[props[0]] = keys[1];
b[props[1]] = k[keys[1]][next];
var c = {};
c[props[0]] = Object.keys(key)[0];
c[props[1]] = value;
arr.push([a, b, c]);
};
next = -1;
}
return arr
});
}));
}
document.querySelector("pre").textContent = JSON.stringify(
p(settings, props), null, 2
);
<pre></pre>
I have a Javascript Array of objects as follows
var data = [
{
id: 1,
date : '1/1/2011',
todo : 'Maths'
},
{
id: 2,
date : '1/1/2012',
todo : 'Science'
} ................. and soo on
];
I want a resulting data as
var newArray = [
['1/1/2011', '1/1/2012'],
[
{
id:1,
todo: 'Maths'
},
{
id:2,
todo: 'Science'
}
]
]
How can I do that in Javascript efficiently ?
function prepare(data) {
var result = [ [], [] ];
for(var i = 0; i < data.length; i++) {
result[0][i] = data[i].date;
result[1][i] = { id: data[i].id, todo: data[i].todo };
}
return result;
}
var newArray = prepare(data);
try
var data = [{
id: 1,
date: '1/1/2011',
todo: 'Maths'
}, {
id: 2,
date: '1/1/2012',
todo: 'Science'
}];
var array = [];
data.forEach(function (item) {
array.push(item.date);
delete item.date;
})
data.unshift(array)
console.log(data)
I have tried. Its working
var data = [
{
id: 1,
date : '1/1/2011',
todo : 'Maths'
},
{
id: 2,
date : '1/1/2012',
todo : 'Science'
}];
var newArray=formatStr(data);
alert(JSON.stringify(newArray));
function formatStr(data){
arr1=[];
var arr2=[];
for (var i in data) {
var obj={};
obj["id"]=data[i].id;
obj["todo"]=data[i].todo;
arr1.push(data[i].date);
arr2.push(obj);
}
var result=[arr1,arr2];
return (result);
}
If you can use jQuery, then this will work:
var newArray = [[], data];
$.each(data, function(i,v) {newArray[0].push(v.date);delete v.date;});
For pure javascript, this will work:
var newArray = [[], data];
for (var i=0; i<=data.length; i++) {
typeof data[i]==="object" ? (newArray[0].push(data[i].date), delete data[i].date) : '';
}
Split array of objects into new array or objects based on age value in Javascript
var items = [
{name:"Foo", age:16, color:"w"},
{name:"Bar", age:18, color:"b"},
{name:"foo", age:16, color:"w"},
{name:"bar", age:18, color:"w"},
{name:"foobar", age:18, color:"b"},
{name:"barfoo", age:20, color:"w"}
];
How can I return a list like:
var items = [
{age:16,name:"Foo"|"foo",gender:"w"|"w"},
{age:18,name:"Bar"|"bar"|"foobar",gender:"b"|"w"|"b"},
{age:20,name:"barfoo",gender:"w"}
];
I have worked but i got output with 'undefined' in name. Below is my code.
var data = [{age: 21,name: "Walter",color: "black"},{age: 25,name: "sentinel",color: "black"
},{age: 21,name: "Micah",color: "purple"},{age: 25,name: "mike",color: "black"},{age: 21,name: "Danny",color: "white"},{age: 25,name: "mike",color: "black"}];
var obj=data;
var arrayobj = obj.length;
var i, row, arr = obj, ss = {};
for (i = 0; i < arr.length; i++) {
row = arr[i];
ss[row.age] = ss[row.age] || {count: 0};
if (ss[row.age][row.age] === undefined) {
ss[row.age][row.name] = row.name;
ss[row.age]['name']+=row.name+'|';
ss[row.age]['color']+=row.color+'|';
ss[row.age]['count'] += 1;
}
}
console.table(ss);
I'm assuming you want to group the items by their age. Here is one way:
(fiddle)
items.reduce(function(buckets,item){
if(!buckets[item.age]) buckets[item.age] = [];
buckets[item.age].push(item);
return buckets;
},{});
Let's explain:
For each item, if we don't already have a 'bucket' for it, create a new empty one
Add it to the bucket
return the new updated bucket list.
The method returns an object with 3 properties: 16,18 and 20, each containing the objects with that age.
This will work. The output is in different format than one provided by exebook .
Please check and confirm. Here's a fiddle....
** UX Manager
var buckets = [];
for (var item in items) {
var currentAge = items[item].age;
if(!buckets[currentAge]) {
buckets[currentAge] = [];
for (var i in items) {
if (currentAge === items[i].age) {
buckets[currentAge].push(items[i]);
}
}
}
}
var items = [
{name:"Foo", age:16, color:"w"},
{name:"Bar", age:18, color:"b"},
{name:"foo", age:16, color:"w"},
{name:"bar", age:18, color:"w"},
{name:"foobar", age:18, color:"b"},
{name:"barfoo", age:20, color:"w"}
];
var result = [] // THIS IS THE RESULTING ARRAY THAT YOU WANT
function find(age) {
for (var i = 0; i < result.length; i++)
if (result[i].age == age) return i
return -1
}
function append(i, obj) {
result[i].name.push(obj.name)
result[i].color.push(obj.color)
}
for (var i = 0; i < items.length; i++) {
var x = find(items[i].age)
if (x < 0) result.push({ age: items[i].age, name: [items[i].name], color : [items[i].color]})
else append(x, items[i])
}
console.log(result) // PRINT THE RESULT, alternatively you can use alert(result)
The output
[ { age: 16, name: [ 'Foo', 'foo' ], color: [ 'w', 'w' ] },
{ age: 18, name: [ 'Bar', 'bar', 'foobar' ], color: [ 'b', 'w', 'b' ] },
{ age: 20, name: [ 'barfoo' ], color: [ 'w' ] } ]