Write a function named "indexed_kvs" that doesn't take any parameters and returns a new key-value store containing the integers from 0 to 47 as values each stored at a key which is a string containing the digits of the integer. For example the key-value "0":0 will be in your returned key-value store (include both 0 and 47 in your list) (My code below)
function indexed_kvs(){
var d = (dict = []);
for (var i of Array(47).keys()) {
d = dict.push(i);
}
return d;
}
I keep on returning the input 47, instead of the keys and values ranging from 0 to 47. How can I fix this?
Just use a simple while loop and iterate from the end or use a for loop.
function indexed_kvs() {
var object = {},
i = 48;
while (i--) object[i] = i;
return object;
}
console.log(indexed_kvs());
A shorter approach by generating an array and then create an object of the array.
function indexed_kvs() {
return Object.assign({}, [...Array(48).keys()]);
}
console.log(indexed_kvs());
This should work for you.
function makeKeys() {
var d = {};
for (var i = 0; i < 48; i++) {
d[i] = i;
}
return d;
}
console.log(makeKeys())
I have two arrays, keys and commonkeys.
I want to create a key-value pair using these two arrays and the output should be like langKeys.
How to do that?
This is array one:
var keys=['en_US','es_ES', 'pt_PT','fr_FR','de_DE','ja_JP','it_IT']
This is array two:
var commonKeys=['en-*','es-*', 'pt-*','fr-*','de-*','ja-*','it-*', '*']
This is the output I need:
var langKeys = {
'en-*': 'en_US',
'es-*': 'es_ES',
'pt-*': 'pt_PT',
'fr-*': 'fr_FR',
'de-*': 'de_DE',
'ja-*': 'ja_JP',
'it-*': 'it_IT',
'*': 'en_US'
};
You can use map() function on one array and create your objects
var keys=['en_US','es_ES', 'pt_PT','fr_FR','de_DE','ja_JP','it_IT'];
var commonKeys=['en-*','es-*', 'pt-*','fr-*','de-*','ja-*','it-*', '*'];
var output = keys.map(function(obj,index){
var myobj = {};
myobj[commonKeys[index]] = obj;
return myobj;
});
console.log(output);
JavaScript is a very versatile language, so it is possible to do what you want in a number of ways. You could use a basic loop to iterate through the arrays, like this:
var keys=['en_US','es_ES', 'pt_PT','fr_FR','de_DE','ja_JP','it_IT']
var commonKeys=['en-*','es-*', 'pt-*','fr-*','de-*','ja-*','it-*', '*']
var i;
var currentKey;
var currentVal;
var result = {}
for (i = 0; i < keys.length; i++) {
currentKey = commonKeys[i];
currentVal = keys[i];
result[currentKey] = currentVal;
}
This example will work in all browsers.
ES6 update:
let commonKeys = ['en-*', 'es-*', 'pt-*', 'fr-*', 'de-*', 'ja-*', 'it-*', '*'];
let keys = ['en_US', 'es_ES', 'pt_PT', 'fr_FR', 'de_DE', 'ja_JP', 'it_IT', 'en_US'];
let zipArrays = (keysArray, valuesArray) => Object.fromEntries(keysArray.map((value, index) => [value, valuesArray[index]]));
let langKeys = zipArrays(commonKeys, keys);
console.log(langKeys);
// let langKeys = Object.fromEntries(commonKeys.map((val, ind) => [val, keys[ind]]));
What you want to achieve is to create an object from two arrays. The first array contains the values and the second array contains the properties names of the object.
As in javascript you can create new properties with variales, e.g.
objectName[expression] = value; // x = "age"; person[x] = 18,
you can simply do this:
var keys=['en_US','es_ES', 'pt_PT','fr_FR','de_DE','ja_JP','it_IT'];
var commonKeys=['en-*','es-*', 'pt-*','fr-*','de-*','ja-*','it-*', '*'];
var langKeys = {};
var i;
for (i=0; i < keys.length; i++) {
langKeys[commonKeys[i]] = keys[i];
}
EDIT
This will work only if both arrays have the same size (actually if keys is smaller or same size than commonKeys).
For the last element of langKeys in your example, you will have to add it manually after the loop.
What you wanted to achieve was maybe something more complicated, but then there is missing information in your question.
Try this may be it helps.
var langKeys = {};
var keys=['en_US','es_ES', 'pt_PT','fr_FR','de_DE','ja_JP','it_IT']
var commonKeys=['en-*','es-*', 'pt-*','fr-*','de-*','ja-*','it-*', '*']
function createArray(element, index, array) {
langKeys[element]= keys[index];
if(!keys[index]){
langKeys[element]= keys[index-(commonKeys.length-1)];
}
}
commonKeys.forEach(createArray);
console.info(langKeys);
Use a for loop to iterate through both of the arrays, and assign one to the other using array[i] where i is a variable representing the index position of the value.
var keys = ['en_US', 'es_ES', 'pt_PT', 'fr_FR', 'de_DE', 'ja_JP', 'it_IT'];
var commonKeys = ['en-*', 'es-*', 'pt-*', 'fr-*', 'de-*', 'ja-*', 'it-*', '*'];
var langKeys = {};
for (var i = 0; i < keys.length; i++) {
var commonkey = commonKeys[i];
langKeys[commonkey] = keys[i];
}
console.log(JSON.stringify(langKeys));
let keys = ['en_US', 'es_ES', 'pt_PT', 'fr_FR', 'de_DE', 'ja_JP', 'it_IT'];
let commonKeys = ['en-*', 'es-*', 'pt-*', 'fr-*', 'de-*', 'ja-*', 'it-*', '*'];
// declaration of empty object where we'll store the key:value
let result = {};
// iteration over first array to pick up the index number
for (let i in keys) {
// for educational purposes, showing the number stored in i (index)
console.log(`index number: ${i}`);
// filling the object with every element indicated by the index
// objects works in the basis of key:value so first position of the index(i)
// will be filled with the first position of the first array (keys) and the second array (commonKeys) and so on.
result[keys[i]] = commonKeys[i];
// keep in mind that for in will iterate through the whole array length
}
console.log(result);
I have an element structured like this:
Element ->
[{values: arrayOfObject, key:'name1'}, ... ,{values: arrayOfObjectN, key:'nameN'}]
arrayDiObject -> [Object1, Object2, ... , ObjectN] //N = number of lines in my CSV
Object1 -> {x,y}
I have to take data from a big string:
cityX#substanceX#cityY#substanceY#
I thought to make it this way, but it seems like it pushes always in the same array of objects. If I put oggetto = {values: arrayDateValue, key: key}; inside the d3.csv function, instead if I put outside the function it add me only empty objects.
Here is my code:
var final = new Array();
var oggetto;
var key;
function creaDati() {
var newdate;
var arrayDateValue = new Array();
var selString = aggiungiElemento().split("#");
//selString is an array with selString[0]: city, selString[1]: substance and so on..
var citySelected = "";
var substanceSelected = "";
for (var i = 0; i < selString.length - 1; i++) {
if (i % 2 === 0) {
citySelected = selString[i];
} else if (i % 2 !== 0) {
substanceSelected = selString[i];
key = citySelected + "#" + substanceSelected;
d3.csv("/CSV/" + citySelected + ".csv", function(error, dataset) {
dataset.forEach(function(d) {
arrayDateValue.push({
x: d.newdate,
y: d[substanceSelected]
});
});
});
oggetto = {
values: arrayDateValue,
key: key
};
arrayDateValue = [];
final.push(oggetto);
}
}
}
Any idea ?
First you should make the if statement for the city and then for the key, which you seem to be doing wrong since you want the pair indexes to be the keys and the not pair to be the city, and you are doing the opposite. And then you need to have the d3.csv and push the objects outside of the if statement, otherwise in your case you are just adding elements with citySelected="".
Try something like :
for(var i = 0; i < selString.length -1; i+=2){
cittySelected = selString[i];
substanceSelected = selString[i+1];
key = citySelected + "#" + substanceSelected;
d3.csv("/CSV/"+citySelected+".csv", function(error, dataset){
dataset.forEach(function(d){
arrayDateValue.push({x: d.newdate, y: d[substanceSelected]});
});
});
oggetto = {values: arrayDateValue, key: key};
arrayDateValue = [];
final.push(oggetto);
}
It's is not the best way to do it, but it is clearer that what you are following, i think.
In the if(i % 2 == 0) { citySelected = ... } and else if(i % 2 !== 0) { substanceSelected = ... } citySelected and substanceSelected will never come together.
The values should be in one statement:
if(...) { citySelected = ...; substanceSelected = ...; }
The string can be splitted into pairs
city1#substance1, city2#substance2, ...
with a regex (\w{1,}#\w{1,}#).
Empty the arrayDateValue after the if-statement.
Hint:
var str = "cityX#substanceX#cityY#substanceY#";
function createArr(str) {
var obj = {};
var result = [];
var key = "";
// '', cityX#substanceX, '', cityYsubstanceY
var pairs = str.split(/(\w{1,}#\w{1,}#)/g);
for (var i = 0; i < pairs.length; i++) {
if(i % 2 !== 0) {
key = pairs[i];
// d3 stuff to create values
obj = {
// Values created with d3 placeholder
values: [{x: "x", y: "y"}],
// Pair
key: key
};
result.push(obj);
}
// Here should be values = [];
}
return result;
}
var r = createArr(str);
console.log(r);
May be you can do like this;
var str = "cityX#substanceX#cityY#substanceY",
arr = str.split("#").reduce((p,c,i,a) => i%2 === 0 ? p.concat({city:c, key:a[i+1]}) : p,[]);
console.log(JSON.stringify(arr));
RESOLVED-
The problem is about d3.csv which is a asynchronous function, it add in the array when it finish to run all the other code.
I make an XMLHttpRequest for each csv file and it works.
Hope it helps.
I am trying to sort my object keys.
But when I'm printing my object, it always print bb first. Can anyone explain this?
It should print aa first ? I already sorted my keys.
My first key should be aa and then second should be bb.
Here is my code
var data = {
bb:"bb",
aa:"cc"
};
Object
.keys(data)
.sort();
console.log(data)
DEMO
Two things:
objects in JS have no order of elements, like arrays do
Object.keys returns an array of object keys, it does not modify the object itself, see the following example:
var data={bb:"bb",aa:"cc"};
var arr = Object.keys(data);
arr.sort();
console.log(arr); // the array IS modified,
// but it has nothing to do with the original object
try this
var data={bb:"bb",aa:"cc"};
var keys = Object.keys(data);
keys.sort();
var obj = {};
for(i = 0; i < keys.length; i++){
obj[keys[i]] = data[keys[i]];
}
console.log(obj);
There is not any method for sorting object keys in JavaScript but you can do this by a object prototype like this.
Object.prototype.sortKeys = function () {
var sorted = {},
key, a = [];
for (key in this) {
if (this.hasOwnProperty(key)) {
a.push(key);
}
}
a.sort();
for (key = 0; key < a.length; key++) {
sorted[a[key]] = this[a[key]];
}
return sorted;
}
var data = {bb: "bb", aa :"cc"};
alert(JSON.stringify(data.sortKeys())); // Returns sorted object data by their keys
I have a list of objects all named in this fashion:
var p1 = {};
var p2 = {};
p1.name = "john";
p1.hobby = "collects stamps";
p2.name = "jane";
p2.hobby = "collects antiques";
I know how to loop through p1 and p2 to collect the properties, provided I know how many of these p object literals there are. Here's my problem, I don't always know how many of these p object literals there will be. Sometimes it goes up to p2, sometimes it goes up to p20.
Is there a way to loop through objects if I know they all share the same prefix?
Edit: I can't change how I'm getting the list of objects. It's given to me in that format...
If we make the following assumptions:
The objects are global
The number suffixes are sequential
...then the following works:
for (var i = 1; window["p" + i] !== undefined; i++) {
console.log(window["p" + i]); // loop over each object here
}
You should have them in an Array referenced by a single variable.
var p = [];
p.push({
name:"john",
hobby:"collects stamps"
}, {
name:"jane",
hobby:"collects antiques"
});
Then you'd loop the Array, and enumerate each object...
for( var i = 0; i < p.length; i++ ) {
for( var n in p[i] ) {
console.log( p[i][n] );
}
}
EDIT:
It seems from a comment that these may be arriving as individual variable.
If they're global variables, and if they always have the same p1 naming, then you can access them as properties of the global window object.
var obj;
for( var i = 1; obj = window['p' + i]; i++ ) {
if( typeof obj === 'object' ) {
for( var n in obj ) {
console.log( obj[n] );
}
}
}
This loop will run until a p(n) global returns a falsey value.
So as long as a truthy value is found, and its typeof is 'object', you'll iterate that object.
If you have all your data stored in a variable , or a few variables you can push it into the array.
var data = "....JSON";
var a = [];
a.push(data);
Push keeps adding stuff into the array in basic sense.
You could also pop to remove the last pushed data.
Take a look at the other methods here:
http://www.w3schools.com/jsref/jsref_obj_array.asp
https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Array
Why don't you just store them all in one top-level object literal? It will make it easier to enumerate through them.
EG:
var MyObj = {
p1: {},
p2: {}
};
etc..
[edit]
If they are local vars, are you can't change the format of this data, you might have to use eval.
Don't shoot me:
var p1 = {};
var p2 = {};
p1.name = "john";
p1.hobby = "collects stamps";
p2.name = "jane";
p2.hobby = "collects antiques";
var found = true, c = 1;
while(found) {
try {
var obj = eval('p' + c);
c++;
console.log(obj);
} catch(e){
found = false;
}
}
I don't suggest using this, I suggest changing the format of the data you are receiving, but this is one possible solution.