Hi all just wondering why the following code results in NaN?
function multiply(num1,num2){
var total = num1 * num2;
return total;
}
var numbers = Array(10,2);
var results = multiply(numbers);
alert (results);
Thanks
4 Answers
Use .apply to invoke the function.
var results = multiply.apply(null, numbers);
The .apply method invokes the multiply function, but accepts an Array or Array-like collection as the second argument, and sends the members of the collection as individual arguments.
FYI, the first argument to .apply sets the calling context. I passed null since your function makes no use of this.
This technique is especially useful if you decide to have your multiply function take a variable number of arguments. Using .apply, it won't matter how many are in the Array. They will be passed as individuals.
Comments
You're only passing one argument to multiply. Inside the function num1 is an array and num2 is undefined.
What you want to do is this,
var result = multiply(numbers[0], numbers[1]);
Comments
you are passing an array into multiply where multiply expects 2 numbers.
when you try to multiply an array it makes sense that the result is NaN which stands for Not a number.
try:
var results = multiply(numbers[0], numbers[1]);
Comments
When calling array values, you must define the value in the array.
For example:
var numbers = Array(10, 2)
JavaScript starts the array count at 0, so numbers[0] would be equal to 10 and numbers[1] would be equal to 2.
1 Comment
scrappedcola
this doesn't really answer the problem. The issue is with the method of calling the function multiply not that the OP isn't defining the array as you mention.
multiply.apply(null, numbers);