Having a bit of trouble with a straightforward question.
Why is it that the following code returns undefined?
var testvar={};
testvar[1]=2;
testvar[2]=3;
alert(testvar.length);
edit I mistakenly wrote testvar[1].length. My intention was actually to write testvar.length
The reason 2 does not have a length is because it's a number, not an array.
If you intended to find the length of a variable named testvar, you should use testvar.length. However, this will also be undefined as objects created with { ... } notation do not have a length property.
In Javascript, only arrays have a length property:
var testvar = [ ];
testvar[1] = 2;
testvar[2] = 3;
alert(testvar.length); // 3
It's important to note that arrays in Javascript start indexing at 0 and can be sparse or non-sparse. This is why the result is 3 instead of 2. For more information on when arrays are sparse, refer to this article.
In this scenario, testvar[1] represents the value stored in that specific index of the array, which happens to be the number 2. Keep in mind that numbers do not possess a length property, so attempting to access 2.length will result in an undefined value. To retrieve the length of the entire array, you should instead use testvar.length.
There is no length method in the Integer data type. You should consider using a string instead.
var sampleVar={};
sampleVar[1]="Hello";
alert(sampleVar[1].length);
In the scenario where length is not defined, you have the option to implement the following solution:
function count(array){
var count = 0;
for(i in array) // 'in' returns key, not object
if(array[i] != undefined)
count++;
return count;
}
var totalAmount = count(array);
const chosenModes = [];
$("input[name='mode[]']:checked").each(function(index) {
chosenModes.push($(this).val());
})
if(chosenModes.length === 0)
{
alert('Please choose a mode!')
};
var myObject = {};
$.each(myObject, function (key, value) {
console.log(key + ' : ' + value); //log the object key and value
});
var nameList = "";
for (var property in myObject) {
nameList += """ + myObject[property] + """;//add object values to name list
}
$("id/class").html($(nameList).length);//display the length of object values.
let myArray = [];
myArray.push(myArray); //add the array value using push method.
for (let index = 0; index < myArray.length; index++) {
nameList += "" + myArray[index] + ""; //show the array value.
}
$("id/class").html(myArray.length); //get the length of the array.
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