I have an array of objects and an array of string and I am tying to combine the two in sequence meaning I would like to first item on the array to be stored only in the first object, second item of the array only in the second object, ect. Something like the following.
var objects = [ obj1, obj2, obj3];
var strings = ["123", "456", "789"];
//Result
var results = [
{
"obj1": {
number: "123"
},
{
"obj2": {
number: "456"
},
{
"obj2": {
number: "789"
}
];
I have been trying to do this with a push and a for loop but I seem to end up with each object containing all three strings.
Its easy:-
for (var i = 0; i < objects.length; i++) {// start loop for getting values one by one from object array
objects[i].number = strings[i]; // assign string values to object array values
}
Matched object and string share the same array index:
for (var i = 0; i < objects.length; i++) {
objects[i].number = strings[i];
}
Or you could do this using the map function:
var results = objects.map(function (value, index) {
return Object.assign({}, value, { number: strings[index] });
});
The other answers are good I just wanted to give you another way. This way you also do not modify the existing objects array
In case you don't know Object.assign add to the first argument (in our case the empty object {}) all the properties from the other object arguments. You can read more about it here: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/assign
Also, you can learn here about the map function: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/map
Related
I am creating project using nodejs. I want to convert array of objects into simple array.For example
var test = [ { id: '1111',
type: 'sdfsdf'
},
{ id: 'df45',
type: 'fsdsdf',
}]
I need
var actual = [111,'sdfsdf'], ['df45','fsdsdf'].
I would propose this solution based on a dynamic number of keys:
var arr = test.map(function(obj){
return Object.keys(obj). // convert object to array of keys
reduce(function(arr, current){arr.push(obj[current]); return arr}, []); // generate a new array based on object values
});
This can be done using Array.map() as follows:
var actual = []
test.map(function(object) {
actual.push(objectToArray(object))
})
function objectToArray(obj) {
var array = []
// As georg suggested, this gets a list of the keys
// of the object and sorts them, and adds them to an array
var obj_keys = Object.keys(obj).sort()
// here we iterate over the list of keys
// and add the corresponding properties from the object
// to the 'array' that will be returned
for(var i = 0; i < obj_keys.length; i++) {
array.push(obj[obj_keys[i]])
}
return array
}
The function objectToArray takes any object and turns it into an array so that it can be flexible regardless of the keys within the object.
How can I convert the below array in to another format as specified below:
My array:
var test=[{"1":"Input"},{"2":"Output"}]
Converted array:
var result=
[
{
"id": "1",
"name": "Input"
},
{
"id": "2",
" name": "Output"
}
]
I tried with this code but not working.
var result = [];
for (var i = 0; i < test.length; i++) {
var newArray = {
id: Object.keys(test[i])[i],
name: test[i].name
}
result.push(newArray);
}
Inner array object doesn't have name property, so test[i].name will be undefined. You need to get the value using the key value. Also you can simplify your code using map() instead of for loop.
var test = [{
"1": "Input"
}, {
"2": "Output"
}];
var res = test.map(function(v) { // iterating over array object
var k = Object.keys(v)[0]; // getting object keys as an array & retrieving first key
return {
id: k, // setting id property as key
name: v[k] // and name property as value
}
});
document.write('<pre>' + JSON.stringify(res, null, 3) + '</pre>');
You should use array.prototype.map for converting an array to another array using a conversion function.
array.prototype.map will iterate on all items and run a "conversion function" on each item.
Since your item is a key-value that looks like this: {"1":"Input"}, the only problem you have is that you don't know the key.
To get the keys of each object you can use the Object.keys method.
var test=[{"1":"Input"},{"2":"Output"}]; // input
var newArr = test.map(function(item){
var key = Object.keys(item)[0]; // get the object's keys and take the only key.
return {id: key, name: item[key]} // return the new object
});
I have not been able to figure out how to properly accomplish this.
I have a JS array of objects that looks like this:
[{"num":"09599","name":"KCC","id":null},{"num":"000027","name":"Johns","id":null}]
I would like to convert this into a simple, single JS array, without any of the keys, it should look like this:
[
"09599",
"KCC",
"000027",
"Johns" ]
The IDs can be dropped entirely. Any help would be really appreciated.
Simply iterate the original array, pick the interesting keys and accumulate them in another array, like this
var keys = ['num', 'name'],
result = [];
for (var i = 0; i < data.length; i += 1) {
// Get the current object to be processed
var currentObject = data[i];
for (var j = 0; j < keys.length; j += 1) {
// Get the current key to be picked from the object
var currentKey = keys[j];
// Get the value corresponding to the key from the object and
// push it to the array
result.push(currentObject[currentKey]);
}
}
console.log(result);
// [ '09599', 'KCC', '000027', 'Johns' ]
Here, data is the original array in the question. keys is an array of keys which you like to extract from the objects.
If you want to do this purely with functional programming technique, then you can use Array.prototype.reduce, Array.prototype.concat and Array.prototype.map, like this
var keys = ['num', 'name'];
console.log(data.reduce(function (result, currentObject) {
return result.concat(keys.map(function (currentKey) {
return currentObject[currentKey];
}));
}, []));
// [ '09599', 'KCC', '000027', 'Johns' ]
You can use Object.keys() and .forEach() method to iterate through your array of object, and use .map() to build your filtered array.
var array = [{"num":"09599","name":"KCC","id":null},{"num":"000027","name":"Johns","id":null}];
var filtered = array.map(function(elm){
var tmp = [];
//Loop over keys of object elm
Object.keys(elm).forEach(function(value){
//If key not equal to id
value !== 'id'
//Push element to temporary array
? tmp.push(elm[value])
//otherwise, do nothing
: false
});
//return our array
return tmp;
});
//Flat our filtered array
filtered = [].concat.apply([], filtered);
console.log(filtered);
//["09599", "KCC", "000027", "Johns"]
How about using map :
var data = [
{"num":"09599","name":"KCC","id":null}
{"num":"000027","name":"Johns","id":null}
];
var result = data.map(function(obj) {
return [
obj.num,
obj.name,
obj.id
];
});
I have some problem with sorting items inside object. So I have something like this:
var someObject = {
'type1': 'abc',
'type2': 'gty',
'type3': 'qwe',
'type4': 'bbvdd',
'type5': 'zxczvdf'
};
I want to sort someObject by value, and this is where I have problem.
I have sorting function that should return key/value pairs sorted by value:
function SortObject(passedObject) {
var values = [];
var sorted_obj = {};
for (var key in passedObject) {
if (passedObject.hasOwnProperty(key)) {
values.push(passedObject[key]);
}
}
// sort keys
values.sort();
// create new object based on Sorted Keys
jQuery.each(values, function (i, value) {
var key = GetKey(passedObject, value);
sorted_obj[key] = value;
});
return sorted_obj;
}
and function to get key:
function GetKey(someObject, value) {
for (var key in someObject) {
if (someObject[key] === value) {
return key;
}
}
}
The problem is in last part when creating new, returning object - it's sorted by key again. Why? And this is specific situation when i have to operate on object NOT on array (yes I know that would be easier...)
Does anyone know how to sort items in object?
Plain objects don't have order at all. Arrays -that are a special types of objects- have.
The most close thing that you can have is an array with the object values sorted . Something like, for example:
_valuesOfAnObjectSorted = Object.keys(object).map(function(k){ return object[k]; }).sort();
You have two possibilities:
Refactor your object into an array
Something like this:
var myObj = [
['type1', 'abc'],
['type2', 'gty'],
...
];
Or even better, since using it somewhere would not rely on array positions but full named keys:
var myObj = [
{name: 'type1', val:'abc'},
{name: 'type2', val:'gty'},
...
];
Use your object with an auxiliar array
Wherever you want to use your object ordered by the keys, you can extract the keys as an array, order it and traverse it to access the object
var ordKeys = Object.keys(myObj).sort(); // pass inside a function if you want specific order
var key;
for (var i = 0, len = ordKeys.length; i < len; i +=1) {
key = ordKeys[i]
alert(key + " - " + myObj[key]);
}
Combination of both of them
If the object is not constructed by you, but comes from somewhere else, you can use the second option approach to construct an array of objects as in the first option. That would let you use your array anywhere with perfect order.
EDIT
You might want to check the library underscore.js. There you have extremely useful methods that could do the trick pretty easily. Probably the method _.pairs with some mapping would do all the work in one statement.
I have a JSON object with the following format:
{
items:{
nestedObj:{
position:3
},
nestedObj2:{
position:1
},
nestedObj3:{
position:2,
items:{
dblNestedObj:{
position:2
},
dblNestedObj2:{
position:3
},
dblNestedObj3:{
position:1
}
}
}
}
}
I am attempting to sort each level of nested object by their position attribute. I can recursively iterate the object, but I don't know where to start for sorting it...
Unfortunately it's not quite so easy to use the sort method as it would if you had an array. So let's build an array:
var tmp = [], x;
for( x in obj.items) { // assuming your main object is called obj
tmp.push([x,obj.items[x].position]);
// here we add a pair to the array, holding the key and the value
}
// now we can use sort()
tmp.sort(function(a,b) {return a[1]-b[1];}); // sort by the value
// and now apply the sort order to the object
var neworder = {}, l = tmp.length, i;
for( i=0; i<l; i++) neworder[tmp[i][0]] = obj.items[tmp[i][0]];
obj.items = neworder;