This question already has answers here:
"Variable" variables in JavaScript
(9 answers)
Closed 7 years ago.
im practicing javascript and i have arrays (more than 10) which have strings in it
var p = ["one","two","three","four"];
var q = [//somthing here]
and another array which is created by a function which select n store some array names for further actions
var m = ["p","q","r","s"];
how can i use element of array m as the varable/array name like:
<button onclick="testArrays(dest, m[0])">desti</button>
must have to work like this
<button onclick="testArrays(dest, p)">desti</button>
all i want to say that how can i use m[0] as a variable
im not using objects
As a variable where? If it's a property of an object you can use object[m[0]]
And if it's on the global scope you can use the window object window[m[0]]. If it's a variable inside a function you should rethink your approach. There is a way that starts with e and ends with val and you should never, ever use it.
Related
This question already has answers here:
How to check if object property exists with a variable holding the property name?
(11 answers)
How to use a variable for a key in a JavaScript object literal?
(16 answers)
Closed 5 years ago.
I'm attempting to run a list of strings through an object. When I do it individually it works, but when I pass it through as a string it doesn't work. How would I fix this?
// this doesn't work
var a = "IntegrationItem1";
var data = faq.a;
// but this works
var data = faq.IntegrationItem1;
What's causing the first example to not work? Is the variable data seeing it as faq."IntegrationItem1" instead of faq.IntegrationItem1?
You can access properties of the object using it's names:
var a = "IntegrationItem1";
var data = faq[a];
what you need is faq["IntegrationItem1"] => faq[a]
This question already has answers here:
Add a property to a JavaScript object using a variable as the name? [duplicate]
(14 answers)
Closed 5 years ago.
I have this snippet of code:
var arrLiteData = [];
for(ii=0;ii<10;ii++)
{
arrLiteData.push({ii:{"field1":100,"field2":ii}});
}
...but instead of ii taking the increasing numeric value of ii, the array just holds the actual variable name, like this:
[{"ii":{"field1":100,"field2":0}},{"ii":{"field1":100,"field2":1}}...etc, etc...
What am I doing wrong?
Many thanks.
Quotes are optional for javascript object keys, so
{ii:{"field1":100,"field2":ii}} is the same as
{"ii":{"field1":100,"field2":ii}} or even
{ii:{field1:100,field2:ii}}. They are just need if you have non alphanumeric characters.
To solve this you could either use a computed key if you're transpiling your code or targeting recent navigators:
{[ii]:{"field1":100,"field2":ii}}
Or build the object in two steps:
var arrLiteData = [];
for(ii=0;ii<10;ii++)
{
var obj = {};
obj[ii] = {"field1":100,"field2":ii};
arrLiteData.push(obj);
}
This question already has answers here:
"Variable" variables in JavaScript
(9 answers)
Closed 8 years ago.
Problem with example:
Variable name: var product5519 = 10;
I can get this name in the form of a String i.e
var str = "product5519"
Is there any way to convert it into variable name so that i can use the value assigned to
product5519
I know one way to solve this problem i.e using eval(str)
If there is any another way to solve it please tell?
Once you are certain creating a global variable was the Right Thing to do, you can add your variable to the window object, like so:
window[str] = 42;
This works because variable lookups end up trying the window object if the variable was not defined in an inner scope.
It's a bit hacky but if you wanted to make a global variable you could do:
var str = "product5519";
window[str] = value;
You could then access the variable like:
window[str];
window.str;
str; // Assuming that there is no local variable already named "str"
you could do something like:
window['product5519'] = 'value'
it may be better to have an array of products, depending on the situation ofc.
You can use an associative array:
var variables = [];
variables['product5519'] = 10;
console.log(variables['product5519']);
This question already has answers here:
Is it possible to define a dynamically named property using object literal in JavaScript? [duplicate]
(7 answers)
Closed 8 years ago.
I have this particular script which uses a javascript dictonary
var z= 'Bingo';
var fruit={ 'Bingo' :1};
var fruit2={ z :1};
alert(fruit[z]);
alert(fruit2[z]);
alert(fruit2['z']);
The first alert gives the expected value 1. However, the second alert gives the alert value as "undefined" and third alert gives the output as 1. Is there a way to use a variable inside a dictionary, ie. can we specify the javascript interpreter to read z as a variable rather than as string 'z'?
Thanks!
Yes, you can do this easily, but not inside an object literal. Property names in object literals are taken literally. They are not variable names. JavaScript quotes them implicitly if you don't quote them.
For example, these two object literals are the same:
{ a: 1 }
{ 'a': 1 }
To use a variable, you need to use [] notation outside an object literal:
var z = 'Bingo';
var fruit2 = {};
fruit2[z] = 1;
This question already has answers here:
"Variable" variables in JavaScript
(9 answers)
Closed 9 years ago.
I can't figure out how to use the name of a variable previously created with eval, without knowing it.
I mean:
function getName(menu_name, level){
eval("var menu_"+level+"="+menu_name);
}
Now how do I get the name of the variable I just created? Probably keep using eval, but I have to put that name into a $.post call as one of my field name.
Thanks in advice.
If level is an integer, you can treat it as a numerical index for an array:
var menu = [];
menu[level] = menu_name;
If level is anything else, you can treat it as a key for a dictionary/associative array:
var menu = {};
menu[level] = menu_name;
Then, for either of the solutions, if you want to access your menu_name, simply call menu[level].