Is the following code valid?
var i;
var objs={};
for (i=0; i <10; i++)
{
objs.i=new FooObject();
}
alert(objs.4.someMethod());
If not, how should it be rewritten to accomplish what I want?
You should edit your code as following:
var i;
var objs = {};
for (i = 0; i < 10; i++) {
objs[i] = new FooObject();
}
alert(objs[4].someMethod());
var i;
var objs = new Array();
for(i = 0; i < 10; i++)
{
objs.push(new FooObject());
}
objs[4].someMethod();
You cannot use numericals for variable names 1. If you want to reference an item by a numerical value, use an array 2. You can then access items by their key in the array. If you want to cycle through, you can use the for...in option 3. It won't matter if your keys are sequential and contiguous:
var x;
var myItems = new Array();
myItems[0] = "Foo";
myItems[9] = "Bar";
myItems[5] = "Fiz";
for (x in myItems) {
alert(myItems[x]);
}
1 http://www.w3schools.com/js/js_variables.asp
2 http://www.w3schools.com/js/js_obj_array.asp
3 http://www.w3schools.com/js/tryit.asp?filename=tryjs_array_for_in
You can't use numbers as variable names, because straight up numbers exist as their own object set in Javascript (i.e, you could think of 4 as already being a global variable that you can't override).
Related
I need to create dynamically name of variable with a loop .
example:
const1 = test;
const2 = test;
const3 = test;
....
I try this , but that only create 20 same variable name in array
I need a unique name increment by 1 at each loop and return each variable to use after.
function createVariables(){
var accounts = [];
for (var i = 0; i <= 20; ++i) {
accounts[i] = "whatever";
}
return accounts;
}
how can I do this ?
Using Object could be the work around
var accounts = {};
for (var i = 0; i <= 20; ++i) {
accounts["const"+i] = "test";
}
console.log(accounts)
If you need variable (not array), then you can use this code:
for (let i = 0; i <= 20; ++i) {
window[`whatever${i}`] = + i;
}
console.log(whatever0)
console.log(whatever1)
//...
console.log(whatever19)
See in playground: https://jsfiddle.net/denisstukalov/thvc2ew8/4/
What is it that you are trying to achieve? As mentioned in some of the comments, and array would be a better approach.
That said, one solution is to set values on a JavaScript object using string indexer (['']). See example below:
function createVariables(obj){
for (var i = 0; i <= 20; ++i) {
obj[`const${i}`] = "whatever";
}
}
// add it to a new object
const accounts = {};
createVariables(accounts);
console.log(accounts.const1, accounts.const2, accounts.const3);
// avoid adding it to global scope (like window)
createVariables(window);
console.log(const1, const2, const3);
Observe:
var groupedLinks = new Array;
for(var i = 0; i < 5; i++) {
linkName = "59notgonnawork" + i;
groupedLinks[linkName] = new Array;
}
I would have expected the result to be the array groupedLinks to be filled up with 5 new keys, the value would be 5 empty arrays.
The actual result in extendscript would be ... grouplinks ... empty.
If I would change this example to be:
var groupedLinks = new Array;
for(var i = 0; i < 5; i++) {
linkName = "notgonnawork" + i;
groupedLinks[linkName] = new Array;
}
It would work perfectly. The only change is the missing "59" at the start of the string used for the array key.
Note that this works perfectly when I run it in console for chrome or firefox. It seems to be indesign and/or extendscript fooling around.
Anything have any ideas why ? I've meanwhile worked around the problem but I'm intrigued.
I would have expected the result to be the array groupedLinks to be filled up with 5 new keys, the value would be 5 empty arrays.
That's exactly what it does, but the way you're viewing the data is likely concealing it because you're not using the proper data structure. Also, property access won't work without using [] because identifiers may not start with a number, so you'd need:
groupedLinks["59notgonnawork0"]
What you're doing isn't meant for arrays, which are expecting sequential numeric indices (though they can technically be assigned other properties too). The type of structure you should be using is a plain object instead.
var groupedLinks = {};
for(var i = 0; i < 5; i++) {
const linkName = "59notgonnawork" + i;
groupedLinks[linkName] = new Array; // Array? plain Object? Depends on its use.
}
Why not trying to push the value in the array on each iteration.
var groupedLinks = new Array;
for(var i = 0; i < 5; i++) {
linkName = "59notgonnawork" + i;
groupedLinks.push(linkName);
}
ExtendScript Arrays are great for stocking data per indeces. If you need key/values objects, why not use… Objects ?
var groupedLinks = {};
for(var i = 0; i < 5; i++) {
linkName = "59notgonnawork" + i;
groupedLinks[linkName] = "Whatever…";
}
alert( groupedLinks["59notgonnawork0" ] ); //"Whatever…"
What is the best way to consolidate this code? As it is, it works perfectly, but it needs to go up to maybe 40-50 items long, so it needs to be shortened dramatically, (I assume, with a for loop).
I'm pretty much a novice when it comes to Javascript, and trying to add arrays to an array with a loop is confusing me immensely.
The "vac1.", "vac2." ...etc, variables are used later on in the code to add pointers onto a Google Maps map.
var x = count.count; // x = a value that changes (between 1 & 50)
if(x == 1){
locations = [
[vac1.vacancy_title, vac1.vacancy_latlng, vac1.vacancy_url, vac1.vacancy_location]
];
}
if(x == 2){
locations = [
[vac1.vacancy_title, vac1.vacancy_latlng, vac1.vacancy_url, vac1.vacancy_location],
[vac2.vacancy_title, vac2.vacancy_latlng, vac2.vacancy_url, vac2.vacancy_location]
];
}
if(x == 3){
locations = [
[vac1.vacancy_title, vac1.vacancy_latlng, vac1.vacancy_url, vac1.vacancy_location],
[vac2.vacancy_title, vac2.vacancy_latlng, vac2.vacancy_url, vac2.vacancy_location],
[vac3.vacancy_title, vac3.vacancy_latlng, vac3.vacancy_url, vac3.vacancy_location]
];
}
...etc etc...
I have tried using a for loop, but it doesn't work and I have no idea if I am anywhere close to figuring out how to do it correctly.
var x = count.count;
locations = [];
array = [];
for (i = 0; i < x; i++) {
array = [vac[i].vacancy_title, vac[i].vacancy_latlng, vac[i].vacancy_url, vac[i].vacancy_location];
locations.push(array);
}
Any help or advice would be greatly appreciated!
Thank you.
You need to consider them as a string:
var x = 5;
locations = [];
array = [];
for (i = 1; i <= x; i++) {
array = ['vac'+i+'.vacancy_title', 'vac'+i+'.vacancy_latlng', 'vac'+i+'.vacancy_url', 'vac'+i+'.vacancy_location'];
locations.push(array);
}
console.log(locations);
Create an array vac and use your previous code :
var x = count.count;
locations = [],
array = [],
vac = [ /* vac1, vac2, ...., vacn */ ];
for (i = 0; i < x; i++) {
array = [vac[i].vacancy_title, vac[i].vacancy_latlng, vac[i].vacancy_url, vac[i].vacancy_location];
locations.push(array);
}
You could use eval for the variable name and build an new array with another array for the wanted keys.
Basically you should reorganize yor program to use a solution without eval. An array could help. It is made for iteration.
var x = count.count,
i,
keys = ['vacancy_title', 'vacancy_latlng', 'vacancy_url', 'vacancy_location'],
locations = [];
object;
for (i = 1; i <= x; i++) {
object = eval('vac' + i);
locations.push(keys.map(function (k) { return object[k]; }));
}
Group the vac* elements in an array and then use slice to cut out as many as you want, then use map to generate the result array:
var vacs = [vac1, vac2 /*, ...*/]; // group the vacs into one single array
var x = count.count; // x is the number of vacs to generate
var locations = vacs.slice(0, x).map(function(vac) { // slice (cut out) x elements from the arrays vacs then map the cut-out array into your result array
return [vac.vacancy_title, vac.vacancy_latlng, vac.vacancy_url, vac.vacancy_location];
});
Because any global variable is a property of the global object :
var vac1 = "whatever";
console.lof(window.vac1); // => logs "whatever"
console.lof(window["vac1"]); // => accessed as an array, logs "whatever" too
You could use the global object and access it as an array to look for your vac1, vac2, vac3 variables :
var x = count.count, i;
locations = [],
array = [],
var globalObject = window; // or whatever the global object is for you
var vac; // this will be used to store your vac1, vac2, etc.
for (i = 0; i < x; i++) {
vac = globalObject["vac"+i]; // the "vac" + i variable read from the global object
if (vac !== undefined) {
array = [vac.vacancy_title, vac.vacancy_latlng, vac.vacancy_url, vac.vacancy_location];
locations.push(array);
}
}
I'm trying, but unsuccessfully, to get the value of a variable, where the variable name is dynamic
var v_1playerName = document.getElementById("id_1playerName").value;
var v_2playerName = document.getElementById("id_2playerName").value;
for (i = 1; i <=5 i++) {
alert(window["v_"+i+"playerName"]);
}
Is this possible?
A simple thing would be to put the variables in an array and then use the for loop to show them.
var v_1playerName = document.getElementById("id_1playerName").value;
var v_2playerName = document.getElementById("id_2playerName").value;
var nameArray = [v_1playerName,v_2playerName];
for (var i = 0; i < 5; i++) {
alert(nameArray[i]);
}
Accessing variables through window isn't a great idea.
Just store the values in an object and access them using square notation:
var obj = {
v_1playerName: 0,
v_2playerName: 3
}
obj['v_' + 2 + 'playerName']; // 3
If you want to keep named references to things you could use an object.
var playerNames = {};
playerNames['p1'] = document.getElementById("id_1playerName").value;
playerNames['p2'] = document.getElementById("id_2playerName").value;
for (i = 1; i <= 2; i++) {
// dynamically get access to each value
alert.log(playerNames['p' + i])
}
I have been searching online all day and I cant seem to find my answer. (and I know that there must be a way to do this in javascript).
Basically, I want to be able to search through an array of objects and return the object that has the information I need.
Example:
Each time someone connects to a server:
var new_client = new client_connection_info(client_connect.id, client_connect.remoteAddress, 1);
function client_connection_info ( socket_id, ip_address, client_status) {
this.socket_id=socket_id;
this.ip_address=ip_address;
this.client_status=client_status; // 0 = offline 1 = online
};
Now, I want to be able to search for "client_connection.id" or "ip_address", and bring up that object and be able to use it. Example:
var results = SomeFunction(ip_address, object_to_search);
print_to_screen(results.socket_id);
I am new to javascript, and this would help me dearly!
Sounds like you simply want a selector method, assuming I understood your problem correctly:
function where(array, predicate)
{
var matches = [];
for(var j = 0; j < array.length; j++)
if(predicate(j))
matches.push(j);
return matches;
}
Then you could simply call it like so:
var sample = [];
for(var j = 0; j < 10; j++)
sample.push(j);
var evenNumbers = where(sample, function(elem)
{
return elem % 2 == 0;
});
If you wanted to find a specific item:
var specificguy = 6;
var sixNumber = where(sample, function(elem)
{
return elem == specificguy;
});
What have you tried? Have you looked into converting the data from JSON and looking it up as you would in a dictionary? (in case you don't know, that would look like object['ip_address'])
jQuery has a function for this jQuery.parseJSON(object).
You're going to need to loop through your array, and stop when you find the object you want.
var arr = [new_client, new_client2, new_client3]; // array of objects
var found; // variable to store the found object
var search = '127.0.0.1'; // what we are looking for
for(var i = 0, len = arr.length; i < len; i++){ // loop through array
var x = arr[i]; // get current object
if(x.ip_address === search){ // does this object contain what we want?
found = x; // store the object
break; // stop looping, we've found it
}
}