I have a dictionary that has the format of
dictionary = {0: {object}, 1:{object}, 2:{object}}
How can I iterate through this dictionary by doing something like
for ((key, value) in dictionary) {
//Do stuff where key would be 0 and value would be the object
}
Object.entries(yourObj).Maps.ECMAScript 2017 introduced a new Object.entries function. You can use this to iterate the object as you wanted.
'use strict';
const object = {'a': 1, 'b': 2, 'c' : 3};
for (const [key, value] of Object.entries(object)) {
console.log(key, value);
}
a 1
b 2
c 3
In ECMAScript 2015, there is not Object.entries but you can use Map objects instead and iterate over them with Map.prototype.entries. Quoting the example from that page,
var myMap = new Map();
myMap.set("0", "foo");
myMap.set(1, "bar");
myMap.set({}, "baz");
var mapIter = myMap.entries();
console.log(mapIter.next().value); // ["0", "foo"]
console.log(mapIter.next().value); // [1, "bar"]
console.log(mapIter.next().value); // [Object, "baz"]
Or iterate with for..of, like this
'use strict';
var myMap = new Map();
myMap.set("0", "foo");
myMap.set(1, "bar");
myMap.set({}, "baz");
for (const entry of myMap.entries()) {
console.log(entry);
}
[ '0', 'foo' ]
[ 1, 'bar' ]
[ {}, 'baz' ]
Or
for (const [key, value] of myMap.entries()) {
console.log(key, value);
}
0 foo
1 bar
{} baz
No, it's not possible with objects.
You should either iterate with for..in, or Object.keys, like this
for (var key in dictionary) {
// check if the property/key is defined in the object itself, not in parent
if (dictionary.hasOwnProperty(key)) {
console.log(key, dictionary[key]);
}
}
Note: The if condition above is necessary only if you want to iterate over the properties which are the dictionary object's very own. Because for..in will iterate through all the inherited enumerable properties.
Or
Object.keys(dictionary).forEach(function(key) {
console.log(key, dictionary[key]);
});
Object.keys(dictionary).forEach(function(key) {… very readable, and compatible.
Object.entries(object).forEach(([key, val]) => {...});
Try this:
dict = {0:{1:'a'}, 1:{2:'b'}, 2:{3:'c'}}
for (var key in dict){
console.log( key, dict[key] );
}
0 Object { 1="a"}
1 Object { 2="b"}
2 Object { 3="c"}
WELCOME TO 2020 *Drools in ES6*
Theres some pretty old answers in here - take advantage of destructuring. In my opinion this is without a doubt the nicest (very readable) way to iterate an object.
const myObject = {
nick: 'cage',
phil: 'murray',
};
Object.entries(myObject).forEach(([k,v]) => {
console.log("The key: ", k)
console.log("The value: ", v)
})Edit:
As mentioned by Lazerbeak, map allows you to cycle an object and use the key and value to make an array.
const myObject = {
nick: 'cage',
phil: 'murray',
};
const myArray = Object.entries(myObject).map(([k, v]) => {
return `The key '${k}' has a value of '${v}'`;
});
console.log(myArray);Edit 2:
To explain what is happening in the line of code:
Object.entries(myObject).forEach(([k,v]) => {}
Object.entries() converts our object to an array of arrays:
[["nick", "cage"], ["phil", "murray"]]
Then we use forEach on the outer array:
1st loop: ["nick", "cage"]
2nd loop: ["phil", "murray"]
Then we "destructure" the value (which we know will always be an array) with ([k,v]) so k becomes the first name and v becomes the last name.
forEach with map above, it's then possible to aggregate values. map will then return a list of said values, thus potentially simplifying the code in other ways.The Object.entries() method has been specified in ES2017 (and is supported in all modern browsers):
for (const [ key, value ] of Object.entries(dictionary)) {
// do something with `key` and `value`
}
Explanation:
Object.entries() takes an object like { a: 1, b: 2, c: 3 } and turns it into an array of key-value pairs: [ [ 'a', 1 ], [ 'b', 2 ], [ 'c', 3 ] ].
With for ... of we can loop over the entries of the so created array.
Since we are guaranteed that each of the so iterated array items is itself a two-entry array, we can use destructuring to directly assign variables key and value to its first and second item.
Try this:
var value;
for (var key in dictionary) {
value = dictionary[key];
// your code here...
}
You can do something like this :
dictionary = {'ab': {object}, 'cd':{object}, 'ef':{object}}
var keys = Object.keys(dictionary);
for(var i = 0; i < keys.length;i++){
//keys[i] for key
//dictionary[keys[i]] for the value
}
I think the fast and easy way is
Object.entries(event).forEach(k => {
console.log("properties ... ", k[0], k[1]); });
just check the documentation https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/entries
${key} ${value}); });using swagger-ui.js
you can do this -
_.forEach({ 'a': 1, 'b': 2 }, function(n, key) {
console.log(n, key);
});
You can use below script.
var obj={1:"a",2:"b",c:"3"};
for (var x=Object.keys(obj),i=0;i<x.length,key=x[i],value=obj[key];i++){
console.log(key,value);
}
outputs
1 a
2 b
c 3
As an improvement to the accepted answer, in order to reduce nesting, you could do this instead, provided that the key is not inherited:
for (var key in dictionary) {
if (!dictionary.hasOwnProperty(key)) {
continue;
}
console.log(key, dictionary[key]);
}
Edit: info about Object.hasOwnProperty here
You can use JavaScript forEach Loop:
myMap.forEach((value, key) => {
console.log('value: ', value);
console.log('key: ', key);
});
myMap is a plain object, not an array.
Map object instead of the plain object that was used in the question.Map object. My bad.
for (let [key, value] of Object.entries(obj)), need Babel.