Question

I’m having a hard time understanding the difference between the comparison and logical “not” operators in Javascript. And I am confused about the syntax as well. My questions are:

Since they are both boolean operators, are there any real differences between the two?

And is the syntax for both like this?
x! = 5

Any explanation appreciated – please post examples if you can.

Answer 1

Comparison: take two values and compare them. We could ask various questions, for example:

• are these two values “the same”, we use == for that
• is this value bigger than that value, >
• is this value bigger than or equal to that, >=

The result of each of this is a boolean value. So we could write:

boolean areTheyEqual = ( x == y );

So aretheyEqual would be “true” if x was equal to y. Now suppose you wanted a variable “areTheyDifferent”. We could get that in two ways, either using the “not” operator, which works on a boolean value:

boolean areTheyDifferent = ! areTheyEqual;

or we could use the “notEqual” comparison

boolean areTheyDifferent = ( x != y );

So the ! operator takes a boolean value and “inverts” it. You need to read the

!=

as a single comparison operator, just like >= is a single operator.